A typical scam: WTS PLEX, VERY CHEAP!

As the first scam I'm showing you a typical one - the PLEX scam. This type of scam is very common since many capsuleers are dependent on this item to get their EVE Online subscription going. In most cases you will get this type of contract linked in the local chat channel at trade systems (Jita, Amarr, Dodixie, Oursulaert, Rens).
Most of the contracts are cheaper than the market value - scammers intend to let you think that you have a very good deal in front of you.

The upper part contains general information about the contract: type, issuer, status, location, etc.
Right below there are multiple lines stating who gets what. Everything you have to pay to the issuer of the contract is colored red - everything you get from the issuer is colored green.
In the example given above you are going to pay 450 million ISK and getting a PLEX.

WRONG! Look carefully:

You will pay 450 million ISK and you will get the PLEX as stated by the colored text "You Will Get/Pay". ADDITIONALLY you will pay a PLEX for the contract. So you get a PLEX from the contract and instantly paying 450 million ISK plus a PLEX totaling a loss of 450 million ISK. 

Most capsuleers don't even look at the bottom part of the contract. Maybe some of the victims think that this is a summary of the contract in a list format. Don't be fooled by this! Better check twice. If in doubt, ask your friends/corp-mates/ally. Heck, don't even hesitate to ask questions in local.

The worst thing you can do is not to ask. There are no dumb questions, just dumb answers - remember that.

Fly safe!