Pawn shops won't work out, they KNOW what stuff is worth and will generally GET a good price for it. I understand the delima you face with your job, mine was the same way. When I was younger man, trying to pay for the house, get ahead, etc. I often thought about a second job, but my primary (on call, extensive travel, work late or early) just never let it happen.
I bought and sold cars along the way, over the years, thats a brutal method, but it's about all I could figure out. I also invested in houses, boats (now THAT was really brutal) and other risky stuff along the way. Made a killing, lost my a$$ or broke even. In the end, I came out ahead (very nicely in fact) but the 'agony of defeat' and the worry about the investment game plan sure takes a toll on you. Investing is NOT for the faint of heart.
I bought some land, with partners, and then bought a house to move onto the land, so far so good. Then when the house was finished two of the hired carpenters refused to move out, claimed we owed them money. Freakin' nightmare getting them evicted, I darn near went to jail I was so mad over the deal (lost our a$$ on that one).
Now that Ferrari cigarette boat, ah there was a deal, broke even. But what a RIDE along the way, I don't regrett that deal for the sheer fun of it all.
Did best buying and selling Jaguars and foreclosure type housing.