Just submitted a deal for some software via Trialpay, and realised that some people might not know about this system. Basically, companies list products on this site. People get the full commercial product (usually software by download) for free, if they take up an offer from one of a selection of advertisers. The company gets paid by the advertiser for the business sent their way, although sometimes they may even choose a charity instead. For example I 'bought' software through Trialpay last year by donating to the Australian Leprosy mission.
It can be hard to find what's available, but the link is to a list of offers currently out there. Some of the apps are unknowns, some are well known. Winrar, Winzip and Zonealarm are there for example. You can even get Xbox subscriptions or marketplace points - although they tend to be pretty popular and sell out quickly.
Anyhow, check out the list. If there's something of interest then just sign up and see if any of the offers appeal. If they do, then if you click through and take up the offer then you'll get the first for free.