DEAR BOB: We put in a bid on a house we want to buy. The agent said we had to include a $1,000 earnest money deposit check, which we did. It has been over a week and we haven't heard if our offer was accepted or rejected. The agent says the seller hasn't made up her mind yet. How can we find out if we got the house or if we get our $1,000 refunded? Mrs. A. W. Suitland.

DEAR MRS. A. W.: It appears you may be a victim of "offer shopping." This can happen if you don't make your purchase offer valid for just a day or two. Some agents even recommend that purchase offers should expire "upon presentation," but I think that puts too much pressure on the seller to decide immediately to accept, reject or make a counter offer. Next time you make a purchase offer, include an expiration date.

DEAR BOB: We will be renting our home to tenants for about a year. What is the best way to determine a fair rent to charge? Cornelia M., Bethesda.

DEAR CORNELIA: The old guideline used to be that a house should rent for 1 percent per month of its market value. For example, if a house was worth $50,000, it should rent for $500 per month.

But in most communities rents have not kept pace with the climb in home values. So your best bet is to "comparison shop" house rentals through the newspaper want ads. Go visit several rentals to see how they compare with your house. Then set your rent based on comparable house rentals. It's usually best to set your "asking price" rent a little on the high side as you can always come down if the house doesn't rent in a reasonable time.

DEAR BOB: We plan to sell our small home soon. Our cost was $47,500 and our mortgage is now paid down to about $34,000. If we pay off the mortgage from the sale proceeds, how will this affect our profit? Mr. D. L., Annandale.

DEAR MR. D. L.: It won't. Your mortgage is irrelevant to your sale profit calculation. Your profit is the difference between your "adjusted sales price" and your "adjusted cost basis."

Adjusted sales price means the gross sales price minus sales costs such as real estate commission and transfer costs. Adjusted cost basis is your original purchase price, plus closing costs which weren't tax deductible at the time of purchase, plus the cost of capital improvements added during ownership. Your tax adviser has further information.

DEAR BOB: We now live just outside of Rome, Italy. But we still own our home near Washington, D.C., where we hope to return in a few years. Since we moved here two years ago, our home has been rented to a nice couple. They just gave us 60 days notice they will be moving out. What is the best way to get good, reliable tenants? Mike L., Rome.

DEAR MIKE: Contact a local realty agent near your home. Many have rental departments that specialize in finding tenants for home and apartment rentals. The fee will probably be about 5 or 6 percent of the gross lease amount. For this fee, the agent should screen prospective tenants, show the house to good prospects, check credit and income background, and handle the other details of the rental.

DEAR BOB: I own some vacant land for which I haven't been able to find a buyer. Is there any way I can trade it for some income-producing property without having to pay profit tax? David B., Gaithersburg.

DEAR DAVID: Yes. It's called a tax-deferred exchange. You can trade virtually any property held for use in a trade or business or for investment if you trade up to a larger such "like-kind" property. You could trade your land for apartments, offices, stores, warehouses or other property. However, you cannot trade it for a property that will become your personal residence. Your tax advisor can answer further questions.

DEAR BOB: We're thinking of buying a bigger home in a better location. Should we first sign the purchase contract or first sell our old home? Susan M., Laurel.

DEAR SUSAN: Sell your old home first.Then you'll know exactly how much cash you have available to buy your new home. If you buy the new home first, then you may be under pressure to get your old home sold and you might have to accept an offer that is lower than the best obtainable.

DEAR BOB: If I die, will my children have to pay capital gains tax on the difference between my cost and the market value of my properties? I recall your saying, some time ago, that the tax law had been changed. Mary G., Laurel.

DEAR MARY: The 1976 Tax Reform Act changed the law in this field and the 1978 Tax Act changed the law back to the old pre-1976 law again. To further confuse matters, the 1978 Tax Act's change in this field expires on Dec. 31, 1979, so we can expect further changes.

For decedents who die before Jan. 1, 1980, their heirs take property at its fair market value on the date of death. All capital gains on the difference between the decedent's cost basis and market value escape taxation (except for estate tax, of course). This is a confusing area of tax law so check with your tax advisor for full details.

DEAR BOB: I would like to become a real estate saleswoman. But, at age 56, I'm too old to study for a license test. Which states don't require such tests to get a license? Mattie M., Fairfax.

DEAR MATTIE: All states require an exam to qualify for a real estate sales license. Many also require successful completion of real estate courses either before of after the exam. For full details of the license requirements in the state that interests you, write to the real estate commissioner at the state capital. By the way, you're not too old to study and pass the license exam. I know people in their 70s who did so and they love selling real estate.

DEAR BOB: Is it true that if I buy a home that has an existing FHA mortgage, I can't get a second mortgage on it? Mr. M. H., Alexandria.

DEAR MR. M. L.: That's not correct. Second mortgages are not allowed at the time a new FHA or VA home loan is made to the buyer. But second mortgages can be put on the property after the purchase or upon resale to another buyer. The person who told you that FHA doesn't allow second mortgages after the initial sale is mistaken.

The new Bruss report, "How to Buy a Home for the Lowest Price and on the Best Terms," is available for 25 cents plus a self-addressed, stamped envelope sent to Robert J. Bruss, P.O. 6710, San Francisco, Calif. 94101.