Chair Slip Covers

I just need to cover 25-35 chairs I guess I could try to do. I try to put a little money. Does anyone have any suggestions? Should I go to the fabric store or just buy sheets / pillow? What about the bow / scarf? Where can I get a template? Thank you!

PS-

I am just learning to use my sewing machine.

Simplicity has a few models to make them
here is the link
http://www.simplicity.com/dv1_v4.cfm?des ...

Are you making these for a wedding? You can also rent, try to understand the fabric you need and the price to make them and compare the rental and make them before taking such a huge task if it was 4-6-8 Chair then I say go ahead, but for the amount you need, ask you never use them again?
Now for the chassis, you could buy bows of tulle and tie with huge rear seats.

http://www.bigdo.co.uk/images/Wild_Pheas ...

Go to HGTV.com AMD DIY Network of sites, they both have thousands of pictures and tutorials