Hi, the simple answer is to use the best you can afford. Cheap strings will give a cheap sound and may make it hard for you to judge if your playing is improving. Cheap strings will not maintain the "good" sound for as long and they will possible wear quicker. Pick a known respected brand, their cheapest would be better that an unknown EBay brand.
Squeaks and squaks, sorry, are caused by bowing technique.
timber and harmonics are enhanced by expensive strings on a quality (read as not-cheap) violin/viola/cello
even a cheap instrument with cheap strings sounds amazing in the hands of a master.
Go to your local store where the public school orchestra students go for lessons and get a set of 'student grade' strings until you develop enough to tell the difference, they won't steer you wrong.
Sorry to tell you Bobby but most squeaks and squeals are caused by bow technique rather than string quality. A set of high dollar strings squeaks as much in my hands as do a cheaper set. With that being said, better strings can definitely improve the sound of your playing and of your instrument. My own choice for under $20 fiddle strings are D'Addario Preludes. I've tried strings costing close to 100 bucks and they sound wonderful but for beginner to intermediate players the Preludes are great and affordable. Here's one place I've gotten them
I feel your pain man. There are at least 4 things I have my students work on with the bow after getting it rosined. #1 is keeping the bow at a 90 deg angle to the strings for the whole up and down strokes. #2 is to experiment with different amounts of pressure on the bow until you get a sound you like. #3 is the speed of the bow across the strings. We do these on open strings without any left hand notes. #4 is keeping the bow hairs flat on the string as opposed to only having one or the other edge of hairs playing. Man, that's a lot of stuff to think about before you ever even play a tune! Other squeaks can come from the left hand when you're playing fingered notes. if the fingers aren't placed correctly. I always warm up with slow/medium tempo scales to get my fingers co-ordinated. I can tell you, I still get squeaks from time to time even with having all this in my head. Oh, I forgot to add what could be #5 and that is to not over tension your bow. Too much tension is bad for the bow and can also lead to unpleasant sounds. Good luck!