As far as your computer goes, they work, are fairly reliable and easy to change the battery yourself. Nothing fancy, but you probably don't really need fancy yet. I've had a couple and they are nice backups IF you can always remember to turn them on before you stow them in your BC prior to the dive as they don't have water contacts and don't work if you turn them on under water. Personally I would sell it as I have my preferences for computers, but a lot of people still use them and they work just fine.
In response to your other comments about hoping to find lead I will offer a suggestion. Lead is super cheap, just pick some up at a recycling yard for around $1.30/lb which is still cheaper than most people charge on craigslist (average $2-3/lb) and significantly cheaper than retail.
Of all the equipment you picked up the computer will most likely be the easiest to sell and ship as they need minimal servicing. If it works perfectly you could probably get $75-90 for it minus fees/shipping, sometimes a little more if you take it diving with you and take a picture of it working at depth as it gives online buyers a sense of security when buying a used computer. The aqualung micra regs you probably get around $85-125 for the full set depending on the condition, usability and just plain old luck on when you list it. Stick them on a tank and see if they leak or have any easily noted issues. As far as if you got a good deal, if I was buying on craigslist I might have paid between $50-100 for everything and felt pretty good about getting a good deal, any more than that and it's not worth the resale risk to me when you add in fees, shipping, unhappy buyers, etc.
