If you buy a sprayer beware there are three or so different basic types. With some of them you lose more paint to the wind than you apply, and you might have to buy three times the amount of paint compared to brush or roller. Also, some sprayers require you to dilute the paint.
I spent a few more bucks and side stepped those issues with the Graco Magnum 257025. There is a surprisingly low expected life, 50 gallons per year. I don't understand the "per year" qualification, it sounds like they're saying I could paint 50 gallons three consecutive years (150 gallons), but that I can't paint 100 gallons the first year.
We went Sherwin Williams for the paint, we might have gone with Benjamin Moore, Wal-Mart Behr, or Ace, but Sherwin Williams had the color we wanted. Expensive, though, I think we paid $45 per gallon. This is why I was concerned about paint loss from the sprayer. SW were having sales (about 30% off) every three months, I don't know if that is still true. Worth it to wait for their sales if it is.