DEAR BOB: In 1973 I bought a nice lakeside lot at a recreational development. Unfortunately, the developer went bankrupt in 1977 before the roads and utilities were put in to my lot. The lots adjoining mine have gone down in value to about one-third of the purchase price. My cost was $16,500 and I now owe a $6,800 balance, payable at $133.65 per month. A nearby real estate dealer has offered me $4,000 for my lot. I really like the place but I'm wondering if I should sell my lot and buy another for a fraction of what I owe on my present lot. I plan to retire in 10 years and would enjoy living at this place, if it's finished by then. John C., Frederick, Md.

DEAR JOHN: I suspect you see the folly of your bad property purchase. In the future, don't buy land, recreational property, or other speculative property you can't personally use within six months. Too many things can and do go wrong if you buy for your far-off retirement years.

If you sell your lot at a loss, and if it was bought for investment, a tax loss deduction is a available. Similarly, if you abandon your lot, tax deductions are available under Internal Revenue Code section 165c. Consult your tax adviser to get maximum tax benefits from your speculation loss.

DEAR BOB: We have been renting our house for the past eight years from a landlord who owns about 35 houses in our area. He plans to sell them this summer. We have first option to buy the house. My income is large enough, but we haven't saved for the down payment and have had credit problems in the past. Is there any way to make a deal with the landlord without a down payment or with a small one? Frank F., Silver Spring.

DEAR FRANK: Yes. You must have been a reliable tenant who paid his rent on time or the landlord wouldn't have given you a purchase option.

Point out to the landlord the advantages of an installment sale with a small down payment. For example, suppose your house is worth $50,000. you might offer several thousand dollars as the down pyament and the rest on a 25- or 30-year mortgage. If the landlord wants cash, tell him how a big profit in one tax year can boost him into a high tax bracket. Also point out the advantages of the interest income with the safety of a first or second mortgage on a house that he knows is good security.