Just a heads up, since it was discussed here, the sack of gems is worth it again, currently selling around 0.50€, i guess it was the glitched sacks that screwed up the marked.
I have some trading card
s (Steam Summer Getaway Trading Card) which I can sell
for 0,07 € (the starting price), that means I can get 0,05 €
(0,01€ to the developers and 0,01€ Steam fee).
If I turn one trading card for gems I get 20 gems
. So 1 gems values 0,05 / 20 = 0,0025€.
If I sell a sack of gems (1.000 gems) for around 0.50€ then 1 gems values 0,50 / 1000 = 0,0005€.
I rest my case.
EDIT: I also have some regular Trading cards (form The Bridge) which I can turn to ONLY 5 gems. I can sell that trading card for 0,08€ (my net gain would be 0,06€. (1 gem =0,012€). I would rather sell all my trading cards and buy the game I want at next sale (which starts tomorrow) rather than bid with gems.