There needs to be an open donation system with a "lay-away" system like star citizen, and shroud of the avatar are using...
http://www.kickstarter.com/projects/cig/star-citizen ,
https://www.shroudoftheavatar.com/ .
By offering something at several different levels with small incentives that can be built up you have a much higher potential to have return backers and also, more backers in general.
Allow players to build up into something similar to making payments but allowing them to just throw in 10-15 dollars here and there and get it bonused towards their maximum "donation/backing". This will allow users who don't have a lot of money up front or in one place all the time to still be able to donate high amounts of cash over an extended period of time rather than only lump sums of money at the time purchased.
Obviously the alpha buy-in is way too high for anyone other than a dedicated fan with a good amount of extra money laying around... Personally it's hard to want to buy in to anything now a days when 99% of games are trash, lie and don't reach any of the goals they describe before release... While this isn't the sole fault of the developers of this game, the consequences of this are consumers and potential investors who are tired of losing and having an unpolished unfinished game presented to them when it's all said and done.
Basically there needs to be more incentives with more things that allow a player to make payments and possible build into something larger with extensive small payments not only large lump sums.
Also, a direct donation paypal never hurts...