The more expensive the better of course, but various signal meters on the market allow a quick check on whether you are pointing at a satellite, or empty space.
If you check in your discount supermarket (Lidl, or similar) then there are the odd bargain receivers tobe had for not much money. The standard sky dish should be your first thing to upgrade though, I would leave it as it is and go for a European kit to run alongside it.
Welcome to the forum by the way, you are embarking on something that will give you plenty of entertainment, and a bit of education at the same time.