You could buy a double mountain bike crankset.
This sounds like the best option if you don't need the large gears, you could get something like a 26/39.
I bought a 9 speed triple mountain bike crankset for $50 bucks that's held up as good as any other crankset I've used, so you could probably go really cheap if you wanted to.
they are worthless with today's gearing options
They allow you to have a tighter cassette, or much lower gearing. You can go all the way down to a 24T on a triple.