I’ve been in the market for a USB sound card for my laptop that hooks up to a home theater surround system, however there is a stark difference in price between the cheap ones on Amazon and say Sound Blaster. A side from a feature difference in these sound cards, is there actual sound quality difference (even though I’m using a premium surround speaker system)?
I'd say, personally to a large extent that might be somewhat opinion based, and/or depend on the specific sound card. Worse, while 'ideal' gear would sound the same on anything, some gear sounds the same.
The worst ones could sound terrible - even with a 'premium' codec chip - but that depends on implementation. That said, 'all' you're looking for is a simple line level output for each channel, and you should have the amplifier bit that does the heavy lifiting.
To most people the feature difference is the big thing - premium sound cards may have things like headphone outs that handle higher impedence headphones (The creative ones certainly do! - and I seem to remember they are designed around that.).
That said, even as someone slightly snobby about audio, I'd say 'get the cheap one first'. They're essentially disposably priced. Try it with your gear, listen to it, and decide if you like it.
I've actually used the onboard sound card and compared it to a 'better' sound card designed for music editing - the differences even with really good kit on the other end are slight and you really need to listen for it to tell.