DEAR BOB: Last October I sold a four-unit apartment house. I got a very good price. Then I read your report about tax-deferred exchanges and Starker "delayed" exchanges. Is there any way I can take the money I got from the sale and reinvest it in another income property to avoid paying the profit tax? Louella C., Annapolis.

Dear LOUELLA: No. A tax-deferred exchange is the only way to avoid paying tax when disposing of investment of business property. Readers desiring more details should read by report "How Tax-Deferred Exchanges Can Pyramid Your Wealth." To get a copy, send a $2 check payable to "Newspaperbooks" for Report 80106 to The Washington Post, P.O. Box 259, Norwood, N.J. 07648.

Dear BOB: Our home has been listed for sale since November. No offers so far. We're selling because of my wife's job transfer. The realty agent says to get the house sold we'll have to take a low down payment and help finance the buyer's purchase. (1) Wouldn't this be dangerous for us if the buyer ruins the house and walks away? (2) As we need to buy another house, how can we do so if we won't get much cash from the sale of our old house? David L., Rockville.

Dear DAVID: 1. - A low down payment home sale is not dangerous for the seller if (a) you check the buyer's credit history and job earnings, (b) your home is located in a neighborhood of stable or rising home values and (c) you don't let the buyer get behind on his or her monthly payments to you.

2. - Your agent is correct that if you expect to sell a home today, it's a virtual necessity for the seller to help finance the sale. Here are 10 low down payment home buying methods which work:

Assume or take title "subject to" existing first mortgage with seller financing balance of purchase price on a second mortgage.

Lease the house now with an option to buy it later, (the rent often can be applied to the purchase price).

If the seller will pay the loan fee, buy with a new VA or FHA mortgage.

No cash down payment but with big monthly payments to the seller on a second mortgage.

A high-yield wraparound mortgage offer can convince the seller to finance your purchase.

For your down payment, offer the seller something you own but no longer want, such as a car, boat, RV or vacant lot.

Borrow your down payment from a bank, credit union, credit cards, cash value life insurance policy or rich uncle.

Offer the seller top dollar in return for his or her full financing for your purchase.

Trade your services (such as carpentry, auto repair, or professional skills) to the seller for the down payment.

Have the seller refinance his or her old mortgage to supply needed cash so you can extend a second mortgage for the balance of the purchase price. c

More creative ways to buy and sell with little or no cash are in Robert G. Allen excellent book "Nothing Down" (Simon and Schuster), available at libraries and bookstores.