In instruments, going for the absolute cheapest one is almost a recipe for disaster. I don't know about violins, but I had piano classes a decade ago and now I'm with clarinet classes. In both cases, the cheapest option would have push me away from the instrument. In pianos, the cheap electric ones are very crappy, usually don't have the full key range, the weight of the keys is non-existent, and sometimes even the size is wrong, not to mention the sound. For clarinets, you can find ones for less than 100 dollars on Amazon, but they sound like crap, the keyboard is fairly bad and they fight you when you want to make a decent sound. If you buy one of these, the most likely outcome is that learning is so hard and unrewarding that you end up abandoning it after a few months.
Usually the best idea is to start out with the entry level range of established brands. I'm not up to date on pianos, but for clarinets that's $500 minimum. Yes, it's more expensive, but if you have at least a basic commitment to learning it's going to pay off. The other option if you aren't sure is getting a loaned or rental instrument, but please don't buy cheapo instruments because that's just throwing money down the toilet.