If I make a PCB using that schematic can I just etch it out myself ( is there any legal issue)
unless they patented it, nope, no problem.
and if you didn't sell it, they wouldn't even care if you copied it . . .
And would I end up saving money rather than buying it?
well . . . time is money . . . and the one you make might not be as reliable
you might also want to look up if that HM 2007 chip needs to be programmed or not . . .