Why not set a few goals for your beta players, and those that meet enough of them do not have to pay for the full release when it happens? Once the beta is available that is. I know I would work my butt off to meet such goals for that kind of reward.
The art of the beta-tester is a dying one. Which is a damn shame, I must say. I remember watching a news-story at some point back in the 90’s about professional beta-testers and I thought those people provided an important and noble service to society. Keep in mind that beta-testers deal with more than merely testing games. Unfortunately early access has changed the entire, ahem, profession to the point where people now have to pay in order to beta-test a game. Something which has had a very noticeable effect on the overall quality of, well, beta-tests.
A beta-tester who payed to beta-test feels entitled, and with good reason. One who gets payed/rewarded has a sense of duty.
Personally I support rewarding beta-testers 100%, obviously. And I know, as a matter of fact, that Zack (all hail!) is of a similar mind. In fact during the 2.0 beta for Siralim the First, I managed to earn a special reward from Zack (all hail!). The standard beta-tester reward was 3 different dyes, I got three times that. How did I earn them? By spamming Zack (all hail!) with suggestions, bug-notices and general feedback, to the point where I suspect he might have become a bit annoyed with me.
Not that I cared terribly about the reward. In fact, I only ever used one of the dyes. I just really, really, really like Siralim and I want this franchise to be the best it possibly can be.
I do believe that a free copy of the game may be a bit much. It’s an indie-title after all and Zack (all hail!) has got bills to pay. In-game rewards one has be to wary of aswel, as they can potentially have an adverse effect on ones enjoyment of the game. Imagine getting a nether-orb as a beta-tester reward. It’d remove that first “flomph yah! A nether-orb!” moment.
Personally I believe one of the coolest and most enticing beta-tester rewards would be to name something in the game after them. Be it bosses (Chumsie the Electric Space Grimoire?), unique items (Chumsie’s Thrice-Enchanted Featherduster!), spells (Chumsie’s Deathly Fingerbang?) or whatnot. It’s simple, easy, has a lasting impact on the game and lets the beta-testers get something truely unique for their efforts.
An added bonus is that adding names to spells, items, etc, tends to make them sound a bit more “magical”. “Disjunction”? Boring. “Mordrekaine’s Disjunction”? Cool!
But, yeah, beta-testers will most likely get rewarded and, as proven by my 2.0 anecdote; there’s a possibility of getting bonus rewards for ones handiwork.