One of the biggest problems in microcomputer software sales is that prospective users have no way of evaluating whether the programs they buy will actually meet their needs. But software marketing methods are changing. Under a new system offered by Soft-Link, a software company in Los Altos, Calif., purchasers are no longer required to fork out the total price on blind faith. Instead, the firm has devised a technique that lets users test software products on their own home or office microcomputers.

Typically, software prices range from $250 to $700 for one program. It's the purchasers, not the vendors, who suffer the consequences of an unsatisfactory program, especially since the selling of secondhand software -- one way for a user to recoup his investment -- is a shady legal area. Soft-Link's new product lets users preview a variety of applications software for just $49.95.

The demo does not provide complete access to a program. Once a user determines that the software suits his or her needs, the demo charge is credited toward the total purchase price. Upon purchase, the dealer issues a code that makes the entire program available.

According to Benjamin M. Rosen, as electronics industry analyst who publishes the Rosen Electronics Letter, the new marketing approach is more complicated than conventional methods, but it "addresses some of the problems faced by both users and dealers." Dealers using the program, Rosen notes, can stock software inventory at substantially less cost; all they pay for up front is the much lower demonstration price.

The software is distributed for Soft-Link by ICO-RALLY, a computer-products merchandiser based in Palo Alto, Calif. Thirteen applications programs are available, including SuperCalc, an electronic spread sheet, and inventory control and filing systems. ICO-RALLY plans to sell through computer retailers initially, then move into office-products stores.