how much cheaper???
My local bike shop charges £20 per wheel not including spokes or nipples, that is just the build charge.
My 1st wheel build took 40 mins per wheel, now I can lace one in about 5 mins. And the sense of satisfaction is immense. Once you learn to lace your own wheels you will wonder why you never learnt earlier.
Study my wheel build how to and then go for it.