Money Hounds

So yesterday my boys were at the neighbors playing in the front yard, and I don't know exactly how it started, but they all started pulling weeds (new house, no landscaping yet). Well the neighbor was really nice and came and paid them $.50 each last night for pulling all of the weeds out of her front yard. The boys were in heaven. They came home today and worked so fast to get all of their chores done. I didn't even have to ask once with any boy. Then, minutes later they were out the door. Cars just came in and asked if I had some glasses he could wear because the wind is blowing and getting dirt in his eyes. I found him some little sunglasses and said what are you doing outside? He tells me, "Jennifer paid us $.50 yesterday for pulling her front weeds, so now we are pulling her backyard weeds and taking all of her rocks to the dirt hill (a dumping place of sorts that the boys love to play on the corner). We are working really hard and hope that she pays us another $.50!" and he was on his bike and off to her house, where her two daughters were also working in the yard with them. I don't know what to do. She's really getting a good deal, they are doing a great job (she LOVED that they did it too) but she didn't ask for it. I don't want to discourage them from working, but in the hopes someone who didn't ask you will pay you? I better do a little better job in Business 101 class tonight with them. Side Note: They are so excited to shovel snow for money this year. They are asking for a weed eater for their birthday so they can mow lawns for money next year, dad's is too heavy and big for them (and for me!) What have we created? Good workers or money hungry animals??? Only time will tell I guess.