I use a Serfas TCPG. It has worked well for several years, and I have no complaints. I just purchased what was on clearance (and had decent reviews) at an online bike parts retailer with whom I was already making an order (so shipping was effectively free or only slightly increased). I think I paid about $12.

I'd recommend buying something of reasonable quality so it will last. That doesn't mean you have to pay a lot.