I need to raise my Speech just 1 more point, and it doesn't seem to be moving when I sell. Could be that it's just so high, each little sliver it goes up is barely noticeable (it's 64, I need 65 so I can buy up to 70 and get Investor).

Am I correct in thinking it's like Oblivion where only the Volume of your items sold goes into raising the skill or is it by Value so the higher the value of the item, the more XP you get? I am just grabbing everything I can carry to sell for the Volume method; but if it's by Value, I should just drop all this JUNK and go back to my house where I have stored the insanely high Value items (saving them for after I get investor).