Having no budget makes things difficult, but I understand having no budget.
Another option is to compress your images and store smaller versions that will still look okay on the web. When displaying images on the web, you do not need high resolution images. The images would still count towards your attachment space, but smaller versions would take less space.
You also don’t say what your web platform is or whether you are embedding Airtable’s shared views or building your own cards. If you know or are willing to learn web development, you can build a simple system for not much more than the cost of web hosting.
