@l2t

I’m self-taught on guitar and mandolin, started fiddle three years ago. I now play fiddle and mando -- they are complementary and reinforce each other very  nicely.

I started with a gift Scherl & Roth student violin. These are made for beginners and are available on eBay for ~$100. It’s a good way to start while you figure out (a) if you want to carry on and (b) what kind of longer-term middle might be good for you. Beyond the beginner level, buying a fiddle is an involving and interesting challenge because, unlike guitars and mandolins, every violin is unique. Gotta try ‘em and compare. I keep my beginner fiddle for just-in-case use.

Bows are just as important. I tried several before I found one that I liked. 

A good set up on violin is just as important as on mando. Experience setting up mando is helpful, but the fiddle bridge is way more diffiult . Violin strings are low tension and easier to work with. Tuning pegs on cheap fiddles are aggravating but fine tuners help.

It will be good if you can get a few beginner lessons. Basic mechanics take time to work out on your own and you end up with some bad habits to unlearn. Ergonomic issues can be very challenging -- repetitive motion injuries are very common with fiddlers. I tried multiple chin and shoulder rests and now play pain-free without a shoulder rest.

Comments above are all correct. This forum is a good resource with interesting and helpful people at various skill levels. Fiddlershop is a class operation with outstanding customer service. Good people.

Finally, learning to play fiddle is an interesting, challenging and fun experience. As everyone says, it is difficult to learn the skills and progress comes slowly. Two steps forward, four steps back. So it is important to manage your attitude to avoid frustration and burnout. 

Fiddle is not as chordal and rhythmic as mandolin, but much more powerful and versatile melodically. Fiddle is hard, but it’s magic when it works.

Strabo

I like stringy’s  comment above.