I personally don't like all purpose saddles.
They don't really put you in a good position for either jumping or dressage, and some can actually encourage bad positions.
If you're only going to be jumping small I'd just get a dressage saddle to start with. If you don't have much money look at some second hand saddles.
Dressage is basis of all english riding, and to be a good jumper you need to do a lot of dressage. My old instructor used to say to me 5 hours of dressage to one hour of jumping, or at least five riding sessions of dressage, to one session focussed on jumping.
If you think of it that way, you'd probably use your dressage saddle a lot more. I used to have a CC and a dressage and definitely used the dressage much more.