I always do the usual things like clean the area of the seal and the crankshaft to remove any rust or debris that could damage the new seal. Right before installing the new seal I rub a light coat of black RTV around the outside edge of the seal to help with stopping the seal from popping back...
Not knowing where your located makes it hard to give a solid response, I am located in New England area and I base my prices off of the age, condition and what I had to put into the machine time and parts wise. A quick basic down and dirty riding mower will start at around $500.00 and go up from...
I purchased a HF plastic welder and I use the black zip ties for the black abs tank welds and the white zip ties for the white or clear tanks with great success. I also purchased the heat stitch tool that uses metal staples that you heat up and press into the larger cracks to give added strength...