Recommendations for Chastity & Extensions

A few things I really have been wanting to do - and I'm thinking about taking the plunge to get the gear.

I want to try chastity. Any recommendations for a newbie, relatively on a budget, unsure it'll be a long-term thing?

Also, one of my favorite fantasies is my gf/hotwife wanting me to be with her - but not being satisfied with my size. So, I'd either use (a) a strapon (likely while in chastity) or (b) an extender/sleeve. Again, any recommendations (pro/con, experience, reviews, price points?)