I need to mount a gear to a motor with a D-shaft.
Where should I get gears like that for a reasonable price and low quantity? Most places I found want you to buy in bulk or want to charge $20 for a 0.5 inch diameter gear, which seems too high to me.
The only kinds of cheap mix & match gears are the tiny plastic injection-molded ones. All the others cost a lot of money--assuming you can even find someplace that will sell in small quantities.
If it is at all possible, switch your design to using cogs and roller chain. This is still a strong positive connection and is way cheaper than gears.