Interesting. I woulda thought this question had previously been discussed in enough detail that there would be no need to ask the question again. But hey! That's what we all love around here, isn't it? I mean, why else would I be joining in on this excellent thread?
You've got solid recommendations above. But I'd like to refer you to another thread. Go to the top of the amps/preamps forum. Look for the tab that says something like "popular all time". At the top of that tab you'll find the thread "Preamp Deal of the Century" which is all about Supratek preamps (which is what I ended up buying). The "budget" Supratek gets rave reviews, has for twenty years, and is right in your price range.
One other thing. Be warned. Once you get one of these preamps you'll spend a lot more time listening to music and a lot less time reading internet Fora....
Just sayin'!
Good luck and enjoy the journey.