Hey guys,

I was offered to buy around 90 minifigures (some complete, some incomplete), but I'm completely at loss whether it would be a good buy. Maybe you can help me, since im very new to both brickvesting and minifigures in General. Price is 170 EUR.

You should try and identify the figures with bricklink, add the total amount of prices and see if it's worth it. 

If I'm correct the fourth row from below, third guy to the left is this one:

http://alpha.bricklink.com/pages/clone/catalogitem.page?M=sw635&name=Luke%20Skywalker%20(Jedi%20Master)&category=%5BStar%20Wars%5D%5BStar%20Wars%20Episode%204/5/6%5D#T=S&O={}

He's worth about 7.50 in used state so if you have more rare figures in that pile it adds up quite fast. 

I would not spend near 170 EUR on that to resell.

Problem you got here is that most of these were available in easy to get sets.  Battle packs, advent calendars, Microfighters, books, you get the gist.  That really limits their market value. 

I would say spend no more than 100 for that.  My rule for larger used minifig lots is to get a rough estimate of what they should sell for then offer half of that.  I offer a little more if there are a few in the collection that I have been wanting for myself.

I would value most of the troop builder figures in the $1.50-$3 range. So no way would I give more than $1 a figure on them. The battle Droids, SBDs, Commando Droids and Assassin Droids are all very very cheap. Several figures (and minikits) came from planet sets, they weren't popular while they were in the stores. The remaining figures from Advent Calendars (including Santa Maul and snowman R2-D2) and books (6 Celebration Han Solo and 4 Celebration Lukes) aren't in high demand because almost anyone that wants them got them already. So, you're left with a bare handful of main characters that might get you some money. $1 a figure is probably reasonable if you want to make a little money on it. $2 is ok if you want them for yourself but are not really concerned with reselling.

Well, after consulting the link provided by BP I came to the same conclusion. However, thanks for confirming my suspicions