I tried a couple different cheapies from Amazon and they seemed to cut at an angle pretty badly, finally got these and they work well. Keep in mind they only cut up to 1" pipe.
I have a super cheap one from Harbor Freight. I use it so infrequently it does not really make sense to spend real money on one. Cuts plenty clean enough for me.
I bought a $35 home depot pair a few years ago and they were great till the blade broke and when i went to buy new blades they were discontinued. So i bought a milwaukee cordless which is pretty good very rugged but the blade could be sharper.