Your probably better of coming up with the money to put another engine in the eclipse.

..by the time you add up the cost of an engine PLUS freight, any additional parts that will probably be needed (water pump, timing belt, etc.), labor to do the swap, then your already past your budget and still carless...

...for a crx, unless you want to have to buy tires and fix dozens of misc. things then you'll probably have to spend $1,500-2+k. Get a LS engine & transmission, motor mounts, shift linkage, etc. and you'll have your budget just about maxed before labor. Might be able to find a first gen CRX and a B16 for a decent price but once you get the above needed parts you'll probably still be passed the budget before labor.

Unless you have the time and patience to look for parts and planning on doing nearly all the work yourself then $3-3,500 isn't quite a feasible amount for what you want, not saying it's not possible...there's just alot more costs than you think.