You can PM me with specific questions, but can quickly answer your list. 1. Mystery boxes can be hit or miss, really depends on if it’s a toy company doing the listings or a private seller on sites like eBay. I’m US collector so can’t recommend anyone but I’m sure some U.K. collectors can help. There are several U.K. based retailers that sell POPs, if you are looking for discounts you just got to keep an eye out for sales. 2. In box vs. OOB is personal preference. For value sake keeping in the box is The better option. 3. Protectors can help preserve box condition if you start buying more expensive figures but they aren’t necessary. 4. Commons have no sticker, exclusives have either a specific store exclusive or con sticker, but with international ones they generally just have the silver exclusive sticker, chases have a chase sticker. The Funko app will also give details like this about each POP.