Assuming this is hand tool only: You might be able to find a wooden rabbet plane for your budget and it can do a rabbet easily enough to gauge lines,with some practice, maybe using a guide strip. The plow is another issue. You might want to investigate making a grooving plane for the groove but it would be a single use type plane with no real adjustments. You might also want to try playing with a saw and chisel arrangement for the grooves. You might be able to do a stair saw with rip teeth to establish the sides of the grooves and use the chisels to finish the groove. Not an elegant solution but workable.