This is what I did, and it works GREAT. I typically get around 85-90% efficiency.
Alternatively, you could use a SS braid. There are tons of articles/videos on how to make those.
Now unless you have a large enough kettle (10 gallons minimum IMO) and a turkey fryer, a cooler and manifold are not going to be your only AG expenses.
You can buy an Aluminum kettle and a propane burner combo online, or you can look for them separately.
I'm not sure how large of a kegging system you want for $250, but it won't be a very large one. You will need either a mini fridge, regular fridge, or a chest freezer and unless you already have one, you will need to buy one or hope you can find one for free on CL. Also, depending on which route you choose, you will need either shanks, tower, or if you're doing the cheapest route, cobra taps.
**AG will probably cost you $250 if you don't have a propane burner, kettle, or MLT.
**Kegging will probably cost you $200 for a two keg system if you've already got a fridge and don't want shanks of tower.
Best place to buy kegging equipment IMO
http://stores.kegconnection.com/StoreFront.bok
If you have any more questions, I'm happy to help.
J