Whatever you buy, consider....
1. getting a pressure gauge
2. lubing the pump with silicone spray
After using silicone spray a few times I now use it on even a new pump. Take it apart, wipe all the surfaces and seals you can get to, then give it a good spray and reassemble.
Yes, you can buy cheap pumps, but with so many people buying new kites (that normally come with a pump) there must be lots of hardly (or never) used pumps lying around just waiting to be swapped for a carton?
Just my $0.02