There are many places to look when purchasing outdoor halloween decorations. There are local halloween specialty stores, wal mart, target, hobby lobby, joann, michaels, and many more.
There are many sites to give you cheap ideas. Some of them are www.halloween-website.com/decorating.html and www.bhg.com/halloween/outdoor-decorations/
I like shopping at Kmart, Target, and Walmart for outdoor Christmas decorations. However, their stock may not be out yet. Check their online counterparts or Amazon for some ideas.
I like to use the Better Homes and Gardens website for my decorating ideas ( http://www.bhg.com/halloween/outdoor-decorations/ ). The great thing about this website is that it doesn't just give you Halloween ideas, but it has ideas for every holiday!
Visit www.HGTV.com. They really have a lot of good and clever ideas for holiday home decorations. They can also provide you with some fun ideas for making decorations for halloween as well.
Martha Stewart (http://www.marthastewart.com/photogallery/halloween-decorating) has a plethora of tips and tricks for Hallowe'en decorating. Better Homes & Gardens also has a large selection of ideas, though they focus more on outdoor decor (www.bhg.com/halloween/outdoor-decorations/).
You can find alot of good ideas for arts and crafts online. A good site for easy Halloween Decorations is http://familyfun.go.com/halloween/halloween-crafts/ Good luck with your students hope you can find something that you and the children will enjoy.
Visit Martha Stewart's website which is MarthaStewart.com. You should also go to hgtv.com as well. Both site will give you great ideas for Halloween decorations.
Making your own Halloween decorations can be a lot of fun and it doesn't have to be expensive. Some great places to get ideas are http://iblue.hubpages.com/hub/Top-10-Halloween-Homemade-Decorations, http://familyfun.go.com/halloween/halloween-crafts/, and http://www.squidoo.com/halloween-homemade-decorations.
It depends on what costumes and decorations you would like to create. You can find some ideas for costumes here: http://costumeideazone.com/. As for decorations, the following site has a lot of great ideas: http://tlc.howstuffworks.com/family/halloween-decorations.htm.
Ehow.com is a website for outdoor decor. How to do things.com is another good site. You can find all sorts of fun things to do. A very good site to look through pictures and ideas.
You can find personalized Christmas decorations at several websites. Squiddo.com has a variety of Halloween themed Christmas decorations for you "dark tree". Or, you can try searching for ideas to create your own homemade decorations.
Home made halloween decorations are very affordable and creative. I like to go to oriental trading to find ideas and supplies for this type of decorating.