I have never regretted spending a few extra dollars (pounds for you, I guess), to get better equipment. Even if you are not "serious" but having fun. The idea is to have fun, not get frustrated when you or someone brings over a real mic or guitar and you have to run to the local music shop to pick up an overpriced cable (those are some of the markup leaders at music shops). And fooling w/ it for hours to get it to work. Then you can't lay down the track because your cheap card's latency is too much for the guitarist to work with. And that cutie you got over to sing thinks yor're a dork. Been there, done that. Kinda takes the fun out the experience.
You should be able to find a "real" interface/soundcard that is the same price or a little above a consumer card. Save yourself some headache. There are plenty of those trying to get into music production w/o spending time on the basic ingredient. Like buying a used car w/ a blown cylinder. It doesn't matter how much you saved, you are going to have to replace the engine if you want to drive it more than a few blocks.