Also, a former coworker of mine works at Keep.com, so that also came to mind.
I guess it's a popular name. His web site does say "Keep – a new, free iOS app" so perhaps it will not be confusing within the scope of Apple's app store and there is no intention for an Android release.
That all said, it looks very nice from the screenshots and I was able to understand the utility being provided from the description. Congrats on the release.
It makes more sense, imho, something that collects till a goal and then makes a single bigger transaction. The goal can also be useful for motivation (3 more coffees and you reach your 100$).