Hi there. It's a bit tricky to appraise a domain name like this because not all people have that special symbol on their keyboards.
It's pretty weird but if I remember correctly a domainer here on NP reported that he sold the (Greek letter z).com. You might want to check that out in the completed sales thread.
Novelty item strictly.
Names like these don't sell.
Why ?
Because they are confusing: people will try to access a.com - which doesn't exist
How are you supposed to reach that domain if the letter is nowhere to be found on your keyboard. The only way is to click a link. But it cannot be advertised or printed on business cards.
There is a reason why this domain was still available.