What incentive does she have to pay this money back? What will happen to her if she doesn't? My bet is the answers are "none" and "nothing". Small claims court will only get you a judgment that she does indeed owe you the money; they're not going to collect it for you (unless you go on some TV court like Judge Judy or whatever, in which case they just pay you rather than having her do it, and you'd both receive appearance fees and hotel stays and meals while you're taping.)

Is there even a chance you could gat your stuff back? You say she is claiming she never agreed to pay you back, but is there possible evidence that she knows she owes you, like email or a text?

If you do get a judgment in small claims court you may be able to get her wages garnished (fortunately you have easy access to her employer) but if she has coworkers who are loyal to her rather than you this could be trouble for you in the workplace if they see you as the bad ex who is harassing her.

Have you talked to her about setting up a payment plan where she pays you back a small amount ($20?) every payday or something? Sure, it will take a while but you have a shot of actually seeing the money sometime soon, unlike SCC which can be a long, drawn out process.

Are you on good terms with her parents? You could ask them to "talk to her, encourage her to do the right thing" in paying you back, and if they're stand-up people they may start nagging her to pay up. Mutual friends and trusted coworkers may also be a help here - it could provide that missing incentive, wanting to be seen as a good person by family and peers. You say this isn't about the money - if you're willing to burn a few bridges, start sadly complaining to everyone she knows, not in a "woe is me" fashion, but a more "something must be really wrong with Ex, she owes me a lot of money and she says she won't pay me back, I think her new boyfriend is a bad influence, back when we were together she would never default on a debt" way.

Barring all this, you may need to consider this a painful and expensive lesson in why one should never "go in" on purchases unless you have signed paperwork between you, like a business partnership or legal marriage,