Everyone is completely missing the point.
The Gekkoscience Compac and 2Pac are strictly SHA256 miners. It isnt possible to mine Litecoin, which is a scrypt currency, with the sticks.
One Scrypt USB miner is the Futurebit Moonlander 2, which has sold out but would be what you would want to look at if you want a Scrypt stick. Keep in mind these are mainly lottery mining units or collectibles and you wont be making hundreds from them.
So what other coins can you mine I really wouldn't like to buy another gpu
With SHA256 miners you mine SHA256 coins (BTC, BCH, PPC,...)
With Scrypt miners you mine Scrypt coins (LTC, DGB, DOGE,...)
In order to really get some money out of mining, you just HAVE to invest a little more. So a GPU rig or a powerful ASIC would be your best bet.