First of all, there are many kinds of trainers. for the budget you've set, I'd completely ignore wind trainers (basically, your wheel will be driving a small fan, which provides the resistance). They are loud, and don't feel that great (but cheap). Then you're left with mag-trainers (magnet based), or fluid-trainers (usually oil, or Kurt uses a "thermal neutral" silicone).
Basically, mag trainers are quieter than wind trainers, but fluid trainers are the most quiet. Some mag trainers allow you to vary the amount of resistance, while I haven't seen a fluid trainer that has one (or needs one). Mag trainers are usually a little cheaper than a fluid trainer, but the fluid trainer usually give a better "road feel". With some older fluid trainers, you may run into leaking problems, but those are usually covered by warranty.
CycleOps is a good brand with several <$300 options. However, I've been doing the same research, and have decided on a Kurt Kinetic Rock'n'Roll. The Rock and Roll and their Road Machine are the same trainers (same resistance unit) on two different bases. The Rock and Roll is a bit more expensive because it allows for side-to-side rocking/leaning motion of the bike, while the Road Machine is the traditional stationary trainer. The Road Machine is just over your budget by $18 ($318 shipped/delivered with Amazon Prime), but I think it's well worth it. It's one of the best constructed and most durable trainers out there, even compared to the CycleOps offerings.
Both Kurt and CycleOps have a lifetime warranty on their stuff, and both have great customer service (from what I've read). CycleOps has been a bigger name for longer, and has a longer track record, and more models. However, search for reviews of the Kurt Kinetic (aka: "KK" - the brand) Road Machine (the model), and you'll find that most people who own one prefer them over the CycleOps offerings. The KK Road Machine design is definitely nicer, and leak-proof, and very quiet, and has a better "road feel". I am liking my Rock and Roll a lot.
I say go Kurt Kinetic Road Machine! My gf has been contemplating getting a trainer for herself so she can train with me, and I'm swaying her towards the KK Road Machine. (it's a little out of her budget, but I'm playing the "buy nice once, cry once" card, since a good trainer will last for years, and her Road Machine will be almost identical to my Rock'n'Roll. On a trainer that is supposed to last for years, why spend $250-290 on something mediocre when you can pay $320 for something great? (comparing the CycleOps Magneto or Fluid2 against the KK Road Machine) Lets say the unit lasts for 5 years, that's a difference of only $6-$14/year, or just over $0.50-$1.20 per month.)