An obvious consideration is style. You have to know what look you're going for. The best way to know that is to really think about your project. Who is your audience? What is your content? Do you have a ton of paragraphs of text or just a few lines and some images? Try to figure that out before you begin looking.
Knowing what you're looking for before you start will go a long way in helping you select something that is right for your project.
You'll know whether you need a highly readable serif or sans-serif typeface for your body text or if you can use something more playful or strong with your few lines of text. Make a list of characteristics, use simple words, and make them your shopping list.
It's easy to get sidetracked and find typefaces that you really like, but aren't right for the project. As difficult as it may be, avoid the temptation to use them anyway and just make a note of them for later. There's always next time.
After you have found and made a short list of possibilities, compare them side by side. Test them out using real content. You'll get a better sense of the true character of the typefaces that you've selected.
When making your final decision, you'll want to check to see how versatile the typeface will be. How many weights and styles it has. The more, the better. You'll at least want to make sure it has a normal weight, true italics, and a bold. Hopefully you'll be able to find one with additional lighter weights, heavier weights and small caps to choose from.
If supporting multiple languages is important, take a look at the font's character set, or see if it tells you in the description which or how many languages it supports.
When cost matters
If you're on a budget, there are some free or low cost services available that could work for you, but whatever you do, don't settle for typefaces that don't match your requirements.
If you're new to selecting typefaces and aren't sure you'll be able to notice the differences in a well made and not-so-well made typeface, you can always start out by looking at very high quality, expensive typefaces first.
Take a look at what is offered by some of the well-known foundries, look at them carefully, try them out with your content, take screen shots. When you know what you like, try out some lower cost options and compare them.
You may notice the differences in quality and you'll be able to search for a typeface that more closely matches your shopping list. Something more affordable, but made well enough that you will be happy with it. Just don't settle.
In the end, you might even decide that the best thing you can do for your website, product, project, whatever it is that you're working on, is to splurge on a typeface or two that will give you the professional, thought-out, clean and polished look that it deserves.
There are some web font services that charge monthly or yearly for access to all or some, or to individual quality typefaces.
Places to look for free to low-cost typefaces:
- Google Web Fonts: http://www.google.com/webfonts
- Check out Beautiful Web Type: http://hellohappy.org/beautiful-web-type/
A lot of times they'll offer a few weights of really nice @font-face web fonts for free.
- The League of Moveable Type: http://www.theleagueofmoveabletype.com/
- Lost Type Co-op: http://www.losttype.com/
- Some foundries offer versions of their high quality typefaces for free for a short time, so check around. A lot of them also offer free trials, you can try them out before investing anything. Here are some foundries to check out: