How do you check contribution value for a game before giving it away?

https://isthereanydeal.com/

Is what I used. That and checking using enhanced steam or looking at the bundle list.

Also when you type the game title it should have stars next to it...

* Reduced value towards your contributor level.
** No value towards your contributor level.

Thanks!

When you seach for a game in the giveaway creation form, there might be one or two stars next to the game's name:
One star means that the game was bundled at least once (or had a 95% discount of US price in any region) and you'd only receive 15% of the US base price as CV.
Two stars mean that the game was once given away for free in a huge amount (rarely at Steam itself, but other stores or gaming websites). For these games you don't receive any CV.

All other games grant full CV (US base price).