Welcome to the forum seese!
There is one SP and one more EP, possibly the last ones, coming out very soon. After that we're all looking forward to the release date of Sims 4. Once those two, SP and EP, come out, you can start looking forward to reduced price sales on other packs. Right now they are offering a lot of double sets at a lower price so I imagine Island Paradise should be lower in 3-4 months. Worst case scenario, ask for it for a Christmas/holiday gift.