Promise rings/engagement rings?

Dated a guy for 3 1/2 years and he gave me 2 rings.. we took a couple years of a break and we got back together and almost been together again for a year and I put my promise ring back on last night I noticed it was broke. I did not break it..I didn’t know it was broke till last night. He knows I don’t like gold. The one that is broke is silver and the other is gold.

He told me I could get another one and I started looking at them but i don’t want him to pay a lot for one. I already feel bad because it’s broke, but I don’t mind wearing the gold because Iv already worn that one. We’ve been talking about engagement rings and he asked what I like so I customized some for him to get the general idea. I’m sure he’s not gonna propose for like the next couple of years only because we’re trying to get on our own feet and have our own place but still I don’t want him to pay a lot for a small promise ring..

Best places to get promise rings that’s affordable and real.. not something that’ll turn my finger green..

Are promise rings even a thing at age 21?

Should he buy another one?

Should I just get the ring that is broke fixed?

Wear the gold one?

My ring finger is a size 4 so it’s gonna be hard trying to find something in a small size.