Sharing internet over USB-- how hard?

[Black]

Thanks.
No wireless in her modem.
Not buying or adding any hardware to get this done-- mostly because I don't have time or a way to get to anywhere to buy it.

Did MDDs have Airport cards built in? I don't think it did . . .

Got an unused router laying around but didn't bring it today.

Glad to know there's no such thing as USB internet sharing, thanks.