This is something that may be dificult. To be honest, you can find hosting that will also cover the cost of your domain for less than $100 per year. This will give you a place to play with designs and promotion, and if you get tired of it you can just abandon it after a year.
If you are really interested there is no more valuable tool than real world experience. Plus it gives you something to work with as you learn from your marketing or programming classes. You will be suprised how much math and logical reasoning you will use if you decide to work on a dynamic site. (using ASP or PHP)
You have already found a very valuable resource (WebMasterWorld) for learning what you need to know online and you will find all of the encouragement you can stand here as well.
If you are concerned with spending money, start with a free Yahoo account, or GeoCities then when you out grow their services you can move on to something bigger.
Good luck, and I hope you stick around.
Oh, one more thing. If you ever hit one of those classes where you just can't see how it will ever be useful. Do your best to keep yourself interested no matter how much of a waste of time it may seem to be. There is always some gold burried somewhere in all of the dirt.