Start with the basic invitation _ There are loads of different styles and types of cards, depending on your budget and how much information you need to include. When you order your samples, try to make sure you have some of each style to see what would work practically for you.
If you're buying your own paper, you can find a good selection at local office shops when it comes to card stocks and glossy photo paper. However, if you're looking for linens or specialty papers, you may have to go online. Always get a sample before buying a huge stack of paper, and do a test print, to make sure that whoever or where ever you're printing from can actually use the paper you've selected with your design and medium. Here are a few other places to buy paper from.