Assuming you can find them used, I recommend you pick up the following for close to the prices I list:
Digitech DigiVerb ($50) - I switch between this and my Electro-Harmonix Cathedral, and the Cathedral costs more.
Line 6 ToneCore Echo Park ($70) - able to do clean digital, analog, or tape/EHX Deluxe Memory Man (knocked my DMM off the board).
I'm unsure what exactly you mean by "boost," so here's three suggestions. Do a little research through Google to see which might best fit what you're looking for:
Digitech Hardwire CM-2 Overdrive ($50)
Digitech Hardwire SC-2 Valve Distortion ($50) - Valve means "Tube" in BritSpeak
Danelectro Cool Cat CTO-1 Transparent Overdrive Version 1 ($50) - The CTO-1 is a clone of the Paul Cochrane "Timmy" pedal. It's the best budget clean boost out there. Be sure you buy a version 1, as Danelectro changed the design for the V2.
Google is your friend.
If you don't care enough to research your own question, why should anyone else care more?
"Pay no attention to his long winded posts... (Explorer) seldomly knows what he's talking about."
"Actual knowledge and a google bookmark are very different things." Anonymous neg-repper