As for how much to charge for shoveling snow, you could use your own home as the standard. Measure out the area to be shoveled and time how long it takes to shovel snow in that area when you're working at full steam. Decide how much to charge per hour of shoveling. If a customer wants an area half the size of your home's then the estimate would be half as much. If the customer's area is twice the size of your home's, the estimate would be twice as much.
To help figure out what your hourly rate should be, ask around the neighborhood to find out what people think might be a fair rate.
If you live near a commercial area, you might also get some income by offering to frequently check and shovel merchant sidewalks and parking lots during a snowy day.