Don't buy more cartridges, buy "Sure Cuts a Lot 2" and use any free font or Free SVG file you can find online ( litterally thousands and thousands including a ton of disney things they dont even make carts for!)
You just need to find a good website to explain it all ( I think I got most of my info from scrappingtable.com) and I ended up buying my SCAL from her site as it got me a ton of extra images free ( I was still learning how to download them so it was handy to have those pre-installed)
I am not affilated with SCAL or scrappingtable, I am just a VERY VERY happy customer, who will never need another cartridge again!
p.s. SCAL cost me the same price as one cartridge and you must own at least one cartridge to make the cricut run and load properly, no problem since it comes with one.