So im playing at a smaller party, about 100 people or so... and im wondering what kind of speakers i should be looking for (watts , ohms .. sizes) i am very unexperienced in this area.. i dont know much about speakers..
Any help would be appreciated

You could rent yourself a couple of Mackie SRM450 speaks, they go on tripod stands and have lots of volume and quality for 100 people. They have built-in amplifiers and need an XLR signal cable input, so you might need to rent a mixer that has XLR output too if you don't have one.

The 450s rent for about $35 a day each. There are similar self-powered speakers from JBL (Eon 15") and Yorkville etc depending on where you live. Rent them from audio rental or contractor companies, these places also have lots of other stuff, ask them what would be good for your party.

You might want to get a subwoofer too - the self-powered gear is easy to hook up.

http://mackie.com/products/srm450/index.html