the way the vote values work is they round it... so if it shows 0.00 then that means it is 0.004999 or lower... once it hits 0.005 then it will show up as 0.01 because the system rounds... To find out exactly how you vote is calculated, you can go here and type in 1000 x your SP... and then divide it by 1000 to get the decimals.

https://steemnow.com/upvotecalc.html

so if you have 30 sp, then put in 30,000 and see the value (30,000 would give you $7.96) so if you divided that by 1000 you would get 0.00796 ... and that would be your vote value!