For getting started, I would suggest just getting an inexpensive practice amplifier before going crazy and buying a Marshall Stack.

Nowadays the small practice amps will do just about everything you could want. They come with all different types of classic amplifier models that they emulate, can have drum machines already built into them, come with all kinds of cool effects to choose from, and some even have tuners.

I still like my Fender 15G Frontman Series II Guitar Comb that came with my Strat Pak for practicing at low volume levels, but it doesn't have any bells or whistles to speak of.

I have a Peavey Amp that is pretty large, and heavy that I picked up in a pawnshop at a steal of a price. Its really just a keyboard amplifier, but I can run effects through it just fine, and I can also plug my acoustic into it if I really want it to get loud. I can also plug my bass into it, and it works for that too.

I recently purchased a new practice amp made by Vox Valvetronix AD30VT 30W Guitar Combo. Its a small tube amp that sounds nice and warm, gets plenty loud for around the house, and doesn't weigh a ton.

I would suggest that you start small, and don't break the bank unless you get to the point of playing on stage. Sure, everyone wants a full Marshall Stack sitting in the corner of a room somewhere in the house, and if you can afford to spend the money an a large amplifier like that, please....go for it!