Possible Clues:

• Hold cheap
• Endure art, think of too little value
• Are turned off when you don't appreciate
• Not more than seven, by the sound of it - don't make too little of it
• If this sounds less than 8, that will not give its true value (9)
• Think too little of the German with awkward external nature
• Don't give full credit below a certain price
• Disparage article worn by true nerd at sea
• You don't appreciate that this is not being one over the eight, by the sound of it
• Each of 11 across is, by the sound of it. Reckon it's not enough?