The easiest way to find out is to get a quote from the Rare Material Trader. Put the 140 ectos in your inventory and talk to the trader. Just like when you buy something, he will give you a quote if you try to sell them, which you can Cancel without actually selling. He will give you a quote per ecto, so you'll have to do the math yourself (but, of course, there is a calculator in Windows).
If the current sell price from the trader is 7.5k, the buy price is probably 6.5k or so = 910K or so for 140
P.s - use the Rare Material Trader, not the Merchant.
P.p.s. The usual price that other players will buy your ectos at, is half way between the Trader's buy/sell prices - in this case ~ 7k. So you would get the most gold by selling to other players (in Kamadan, etc). (140 x 7k = 980k)
Last edited by Quaker; Aug 01, 2012 at 03:16 PM // 15:16..