I think the $10k is a red herring in the short term. You only need to make $2 a day from the $200 (assuming prison food isn't very expensive). You probably don't need to touch the $200, but you do need to work to your strengths.
If you've run a successful ISP, what were your roles? You could list your skills on freelancer sites and offer the service. e.g. if you're technical, then Apache + Perl/PHP + PostgreSQL/MySQL or c# + IIS + MS SQL server or whatever. Start off really cheap to get some feedback, then put your prices up. Gain the trust of your clients to get better work at higher rates, from new clients or existing. I've paid guys on oDesk 10x the rate I hired them for.
If you're more about the content and marketing, sell that. Or if you're more about customer support, offer VA services. If it's a 30 day sentence then just earn some money and don't gamble the $200. Whomever you borrowed it from in prison might not be very forgiving of you lose it.
If it's a long sentence, then you need to earn just a bit more than $2 a day, and use the rest for playing. I suggest trying to find some new niche, or a sub-niche, or a sub-sub-niche - something where you can win. Register some domains, build some content, build some links. Once you've put some money aside you could buy a MajesticSEO or AHREFs account. You could pick up expired domains cheaply and as your pot builds up you could buy nicer domains from Sedo. Or if you have had some good clients from your freelance work, switch to performance based work or do a joint venture.
The main thing is that it's spare money, so you don't need to be afraid to lose it. You can play, experiment, learn. By the time you've got to $10,000 you've made your online mistakes and found ways to make more money than you spend. Fortunately these skills will help keep you busy after you're released so you won't have time for crime, so we won't end up having to throw you back in jail.
