EK, RK, Tsubaki, D.I.D., regina... lots of good chains. What you want to do is scrounge the net and find a site with a good chain sale.
You should change the sprockets too while you are at it. Old sprockets will quickly destroy a new chain.
I would say budget for 200 for all 3 parts. I am guessing you have a 630 chain. You might be able to find a 530 conversion set and that would drop the price a bit.
The ride IS the adventure. The destination is just to get gas!