Here's my chain conversion "kit," and I've got 2 more sprockets on the way.
Paid less than 70 bucks for the stuff in the picture. About $25 for the rear, $14 for the front, and $30 for the chain. Got a 9 dollar sprocket coming and another 10 dollar one on the way as well.
I chose plain roller 530 with 46 rear, 15, 16, and 17 fronts. I figure that I can only get the chain to fit three sprockets at a time without changing the length. No need spending 15 more bucks on an 18t either. I gather the chain was a pretty good deal. It's supposedly good Japanese chain, not the junky Malaysian stuff.
This gearing, with my current tire choice should give me gearing close to stock or
slightly lower with two stages of taller gearing. There is still the option of going even taller than that with an 18t front if I really want to. I'd just have to add a link I guess. Is that alright... adding back links?
I chose the 46 rear partly on price. It was a good compromise between the gearing qualities and wear qualities that I wanted and price. In other words, it was close to what I wanted and cheap.