WP Simple Pay Pro 4.0.0 beta2

A really nice plugin. Easy to set up. Great for donation module. The free version just allow 1$ payment, this one allow free amount by the donator. Infortunatly they doubled the price and it’s a per year cost.
Of course, if you can, buy it, developpers can earn their life, so do it. But if like us, you just need a donation boost that makes less than the cost per year.. just enjoy.