I was thinking $300. Does that seem right? It's a large project, but doesn't involve sizing at all, since it's an afghan, and the pattern isn't terribly difficult. I'd put it at advanced beginner level.
Also, thanks for the help re: attaching different crocheted fabrics together. In the end, what I did was sc along the vertical edges of the grit stitch pieces, then I held the pieces with right sides together and sc them together along the top and bottom through the last row worked and the remaining loops of the starting chain. Then, using yarn and a tapestry needle, I backstitched along the vertical edges, using the holes between the sc edging on the grit stitch pieces as a guide to make sure that my stitches were evenly spaced. It worked perfectly, and if you ever find yourself in a similar situation where you're sewing two dramatically different bits of crocheted fabric together and one doesn't have a very thick edge to it, you may want to give it a go.