A friends 94 altima has a blown head gasket. I was advising her to do an engine swap with another altima as a cheaper route to repairing the head gasket. Anyone have any suggestions? which would be cheaper?

 

i don't know about cheaper...
i'm assuming you are paying a shop to do the work
If the shop quotes it as cheaper to do the engine swap, then I would have some major concerns of the condition of the engine. If they just drop in any old used and abused engine, then you don't know what is about to break on that engine and could end up paying for it. The only way an engine swap would be cheaper than a head gasket job is if they don't take the time to refresh the new engine. I've seen shops do some sketchy stuff when they are swapping in an engine like that. To me, a "new" engine would be a whole can of worms.
But then again, paying someone else to do a head gasket job could be the same kinds of troubles, especially if you don't have a mechanic that you trust.
I would seriously weigh the pros and cons of each option. The unknowns of the new engine are a major turn off for me. For all you know, that new engine has a blown head gasket. Or worse, the oil pump took a shit and as soon as you start it up, it eats itself alive.