Hello,
In Ecwid, you can create different product variations by means of
product options and
product combinations. However, it is currently not possible to make some options to be available or unavailable depending on previously selected ones, like you suggested. There is a related suggestion in our ideas base though:
http://ideas.ecwid.com/forums/22031-...
Please vote for it if you find it useful.
Meanwhile, you can consider creating a custom JavaScript modification on your site that will handle the particular option's selection on the product pages and show/hide text inputs accordingly. Ecwid JS API could be useful for such purposes:
http://kb.ecwid.com/w/page/41188517/JavaScript%20API
If you need help with development of such a mod for your Ecwid store, our colleagues from Qualiteam will be glad to help you. If you are interested in it, please contact them at
sales@qtmsoft.com .