I'm interested in trying to find a training partner in my area to practice at my house. I am strapped for cash and time so martial arts gyms are out for right now. However, I have everything necessary to train at home (multiple sets of pads and mitts, heavy bag, room to train). Ideally I'd like to find someone with a certain degree of knowledge and skill in stand up and ground game, as I do. I really don't want to have to teach someone. My question is, where should I look for a training partner online/offline? I checked craigslist but didn't see any posts that were relevant.
Aside from meetup sites, you may want to consider also considering if local gyms have bulletin boards or forums you can use. You might not be able to always get out to the gyms, but some of the people going to the gyms might have the time to get to you - and they might be looking for someone with good skills as well.
That said, the hard reality is you may HAVE to spend a little time doing teaching depending on where you live and the general "density" of skilled folks around. There might be someone with good ground game but not standing, or vice versa - and you'll have to do a little bit of helping them get their skills up to be worth practicing with.
The unfortunate reality is that this is part of what you end up paying teachers/trainers/coaches for - having someone around who is skilled and trained enough to help you push past your limits. The better you get, the less folks you're going to find who fit that bill.
So you basically end up with a choice - is it better to take the time to get someone up to where it helps you to train with them, or do you solo train until you can find someone who is already at that level and logistically available?
Gracie garage can be an option as well. People register their residence as a meetup for practicing bjj. https://www.gracieuniversity.com/students.aspx?enc=HST8o1nQgbBCO5J0PXPkTQ%3d%3d
It depends if your goal is to screw around or learn and improve at fighting.
If you want to just screw around go ahead and find someone on Craigslist or whatever. You will not improve by just winging it with some randoms, but if you're just trying to have some fun, go for it. Try not to kill eachother.
If your goal is to learn and improve as a figher/martial artist, you will need legitimate instruction, and structured, full contact sparring. I assume because you even asked this question that you are inexperienced. Save your pennies and join an MMA gym. You will get more out of a month of legitimate training than you will from years of messing around in your garage. I can promise you that.
What to do in the mean time while you're saving? Lift weights. Exercise. Play other sports that rely on explosive movements, balance, and agility (basketball, etc.), or whatever you think is fun. Just stay active so your body is ready to be broken down by martial arts training.