If price is an issue, you can hardly go wrong with a good vintage Singer. I love my old Singers... and they are on Craigslist for cheap, all day long! They are usually overpriced on Ebay, and then you have to trust the seller's expertise in shipping-- which can be a disaster. Look on your local Craigslist.
The Singer 301 is a very light, portable machine that can also go into a cabinet at home. The feed dogs can drop for FMQ.
You can do a lot of 'walking foot' straight line quilting with any of the machines.
There is no one machine that most quilters use. You just have to find the one that's right for you.