What IP to choose it depends on where you are located and what websites do you want to access. For example, if you are going to UK and you want to rean early a car, for you it will be more suitable to choose UK IP because in this case, you will have the best discounts and cars. I've checked it myself, so I'm experienced in this question. I've found out about VPN from https://vladtalks.tech/vpn/how-to-set-up-vpn-on-router and all other tricks with discounts and website access also took from there.