MAME .37b7 + my roms weigh in at 100mb

I have some old ddr sticks laying around somewhere, but I'm not sure if any of them were bigger than 64mb.
I really don't want to sink
any money into this.
My regular setup is modern and runs everything I want it to.
The main reason that I'm bothering with this is to have a seperate system with a 4-way joystick.
Also have a spare Compact Flash to IDE adapter, but would have to buy a card.
It would probably be the right choice for a bartop. Less space, less heat.
But I will probably use a 10gb hd that is sitting around and I have no other use for.
I'm a novice and haven't worked with DOS since I was a kid. I have picked up a few command lines from working with these emulators.
After doing some research, I'm leaning toward finding a copy of windows 95, so I can set up my folder structure, etc in windows, then change it to boot to dos.
I have plenty of t-molding, wood, etc.
All I should have to buy is a joystick, 1P button & keyboard encoder (or attempt to hack the keyboard that came with this computer).
I'm going to go ahead and set up the software before I spend any money.
Not sure when I'll actually get around to building it. I have a driving cab that I want to redo the control panel and front end for first.