Buying a ready made 4×4 Scrim Jim frame can be quiet expensive however there are many ways of making your own frame from either wood, plastic or metal. On this video the good people from cheesycam take a very simple approach of using a simple tool free metal frame that you can get at any local hardware store to use as a makeshift Scrim Jim frame very very little money.
There are many cool frame solutions that can help you with all your large gels, diffusers, reflectors etc. Some of the larger ones can easily go in price to over several hundred dollars (depending on size and the manufacturer). Now you can always just build a wooden frame but it can be a bit heavy and not necessarily something that you can take with you on the go or disassemble and reassemble without tools.
A simple option is to use metal frames that normally are used to hang mesh nets on doors and windows. There are ready made solutions which are pretty affordable (around $20) and should be strong enough and simple to assemble with no tools and are light and easy to travel with and they come in different sizes. To connect your frame to a light stand you can use the Python Double Clamp that appears in the video – it isn’t super cheap at $43 but it can be used for all sorts of things.
If you want a relatively inexpensive solution that only require an Allan key you can check out the Collapsible Strobius Frames in the video below (it cost between $65-$107 depending on the size).