Common loose - $2-3
Common MIB - you will be lucky to get $5, what you probably paid for them
more desirable loose - $5-7 (non core 7, unicorns, 3d symbols, divine shine, cutie cascade, pegs)
more desirable MIB - $6-10 depending on who it is
and of course the rare or HTF ones will depend on who you have.