Do you have an idea how many I can expect to mine on a monthly basis with one?
if you get Apollo with 3th you would expect to make about $12 or 0.00038
BTC per month (before the power bill).
You can use this simple
calculator to calculate different hashrate, but keep in mind that these numbers do change depending on the difficulty and price of bitcoin.
Usually the power bill would be much greater than that, or even if in a third world country, then still very close to $12, so if you ask me, mining with any of the devices (a single one) mentioned in the first post is a complete waste of time, except for perhaps the USB miner which I don't expect to use that much energy (I wouldn't mine for that little profit, personally).
I would get some miner with at least a few TH so you don't get completely left behind the block mining race. 200-500GH/s is simply too low to be reasonable even for lottery mining.