I started collecting Motown related stuff myself about a year ago , dont know why I never bothered before (Soul Snobbery I Reckon !! ). Anyway , I love White demos and have picked up some gems for bugger all , Marvelettes - Destination Anywhere £6 / David Ruffin - Walk away from Love £4 / Isley Brothers - This Old Heart £6 etc., etc.
Plus loads of issues of great Northern stuff , Ask the Lonley , Love Guess Who , My Baby Loves Me , all for under £15. The thing is so many are great records both sides.
To be honest it's more affordable to me but there are so many great records out there for peanuts and lets not forget Motown is basically where our scene evolved from.
Good luck and enjoy
Cheers
Swifty