When is it okay to buy a sex toy with your partner?

I've been abstinent for over 2 years now and I'm not breaking that for another 2, but I like sex... a lot. I don't have any proper sex toys and I really want one but my boyfriend wants to go pick it out together so it's not a monster compared to his. I'm fully on board with the picking it together thing, but I don't know when it's been long enough to pick it out together. Advice is much wanted.