Helo Kirra000
It might be cheaper rather than buying them ready made to get some Anita cards and stick two together. Anita card stock is quite good value and come in largeish packs.
You just stick the back of one card to the inside front of the other and then you have your gate fold. It also give some stability to the card if you plan to decorate the front heavily as sometimes the don't want to stand up.