Vine accounts are on the lower end of the chart (price wise) when it comes to their value. The truth is that even popular Vine accounts that have millions of followers and loops are rarely worth more than a few hundred dollars. For example, a 100K followers Vine account generally sells around 100-200 USD, while a Facebook fanpage in the same size range is worth five times more.
Update: Since Vine is shutting down, our company will no longer purchase Vine accounts. You may read more about this here: http://viralaccounts.com/r-i-p-vine-twitter-is-shutting-down-vine-so-were-halting-vine-account-sales/