I have a totalled 94 Camry with an I4 (got rear-ended). Everything from the backseat forward is perfectly fine.

I found a great 94 Camry with a V6. Before I buy, I'm wondering how hard and how costly it would be to put the I4 in the new car. I've heard about $300 for an engine swap, but don't know what anything else would run.

 

It will cost a lot more than $300 to do the swap unless you are doing it yourself and don't break anything.

 

What is your goal? Does the car with V6 engine run OK? If so what reasons to replace engine with 4-cylinder?

As Patonium states, if not doing all your own work your going to spend a lot more then $300.

 

The V6 doesn't run and I can get it cheap. So I'm trying to see if it would be worth it to put that I4 in there. I'm guessing a transmission and wiring setup will need to be switched over to the new car as well?

And that $300 number was just a figure I received if the motor matched up.

 

Yes, the wire harness, tranny, etc. will all need to get switched over. That $300 figure might have been for same engine change out so they could just unplug connectors, remove engine and tranny, and then install replacement and just plug connectors back in. Basically, plug and play engine swap. V6 to 4 is not this. If you buy the V6 it would be cheaper to replace with a V6.
Do you know why the V6 doesn't run? Maybe repairable?