By Elizabeth M. MacDonald

(MONEY Magazine) – Thinking about borrowing? Now may be the right time. Interest charges on mortgages, home-equity loans, auto loans and credit cards are all at their lowest in years, and some may go lower yet. Here's a rundown of the opportunities: Mortgages haven't been this cheap since Secretariat won the Triple Crown in 1973. Following the Fed's July cut in one key short-term rate, the average 30- year fixed mortgage sank to a 19-year low of 8.12% by August. And first- year rates for adjustable mortgages dipped to an unprecedented 4% to 4 1/2% (see the tables on page 36), helping to hike mortgage applications by 160% since May 1. Some experts think rates will fall even further. ''If the bond market decides inflation is licked, then mortgages could drop another half a percentage point by December,'' contends Philip Braverman, chief economist at DKB Securities in New York City. Others argue rates will stall or climb, though, so you may want to apply now for a loan but let the rate float until closing. By early August, fully 60% of all new loans were refinancings, as homeowners rushed to dump their old high-rate notes. And no wonder: If you swap a 30-year fixed-rate mortgage at 10.5% for a new loan at 8%, you'll cut your monthly payment from $915 (on a $100,000 balance) to just $734 and recoup your $3,500 closing costs in only 20 months. If, on the other hand, you switch to a 15- year note at the prevailing 7.6%, you'll pay a little more ($933 a month) but retire the debt in as little as half the time while saving as much as $160,000 in total interest. Home-equity loans, most of which are tied to the prime rate, have bumped down to a national average of 7.83%. That's an all-time low, since this type of loan did not exist the last time the prime stood at 6% (1973). With their tax-deductible interest, HELs are especially attractive right now for home repairs and autos and for refinancing other debts. You could refinance a $10,000 credit-card balance at 18%, for example, with a 7.83% HEL and cut your interest costs by $1,188 in the first year alone if you're in the 28% tax bracket. Weigh the closing costs, though. Even HELs that don't charge points can have fees as high as $950 -- meaning you would lose on the above deal if you paid off the debt in less than 10 months. With rates hovering at 9.39%, auto loans are the cheapest they've been in 20 years. Credit unions have the best deals, generally charging one percentage point less than banks and dealers do, and often letting you finance as much as 100% of the car, rather than 80%. Go for the loan with the shortest term you can afford. You'll pay $2,385 less in interest, for example, with a three-year $20,000 note at the average of 8.94% (monthly payment: $635) than with a five- year loan at 9.6% ($421). And don't pay more than 1% of the loan's face amount in fees. Though the national average of 18.45% charged by credit cards seems steep compared with other rates, it represents a 10-year low and could decline some more. ''I look for rates to level out at about 16% next year,'' says Robert McKinley of RAM Research, a credit-card tracking firm in Frederick, Md. McKinley says there are now more than 500 cards at rates under 15%, vs. only about 50 in 1987. True, some have high annual fees, tiny credit lines or no * grace periods. But you may still come out ahead -- especially on low variable- rate cards like the 8.9% Visa ($39 annual fee) offered by Wachovia bank in Wilmington. Says McKinley: ''If you're still paying 19.8% on a card, that's your own fault.''