I bought some ai files from fotolia, but I cannot afford Adobe Illustrator. How can I edit/export these ai files without Illustrator. What I really need to do is to make slight changes on the ai file, and export to png/jpg. Is there any free/cheaper alternatives that can work with ai files?
Yes and no. Most apps cant open modern ai directly, if the file is in very old format its no problem. That said, some (by default), AI files are embedded in a PDF file (or old ones in a EPS file). So you can try if adobe reader opens it for viewing by changing the extension to PDF. failing that try ghostview.
You can then open this PDF/PS for editing, in any app that supports this. You may lose some AI specific info. Such as styles, live effects or possibly layers etc...
Acrobat Pro can natively open .ai files and save to multiple formats including EPS.
(Tested on Acrobat 9 and Reader X)