Install a bigger hard drive. Both of you.
What kind of computer? laptop, desktop?
What operating system? Windows? Mac?
For about $70 (US) you can put a 160g hard drive in your laptop and have a lot of space. 400g for $90. For a desktop it costs less.
For a desktop you can bet a 1tb (1000gig) drive for about $100
The only things you need are
1. what kind of drive interface? PATA or SATA.
2. A way to transfer everything to the new drive from the old drive. (Software and a connection like the cable below.)
3. A screw driver and the willingness to take the old drive out and put a new one in.
A product like the one above which will run about $10 lets you hook up a hard drive to a USB port. Just make sure it hooks up to the type of drive you have.