I’ve done a DIY cleanroom before but inherently a DIY cleanroom is likely not going to be compliant. Looking at ISO7 you would need a hard walled structure, and this is not achievable with <1k. If your goal is to make a clean room that works for less than 1K than that is possible, just do not expect it to pass any audits.
For our cleanroom we made the frame from PVC, reinforced with a scaffold made of super struts. We then lined the inside with clear vinyl and used duct tape to attach the vinyl to the frame without piecing it. The floor was also covered in vinyl since operators were always wearing booties inside.
Outside the main doorway we made a “grey” room where operators would put on booties and bunny suits. This was basically the same design as the clean room just on a smaller scale. We had a sealed door between the grey room and the clean room that acted as an airlock. We would step into they grey room and close the outer door, sealed will Velcro and a rubber gasket (this would work well with a zipper). Once the outer door was closed we could open the door to the clean room and the grey room would “inflate” we would then pass through and close the door. This did a good job of keeping contamination low, positive pressure is one of the most important design aspects.
For air flow we used HVAC systems that were built into the room we were building the clean room in, we ducted into the room and added a bunch of HEPA filters in the duct to give us the best shot at keeping contamination low. For the outflow fans we used bathroom exhaust fans that we used silicone to mount into ductwork that we passed through the side of the clean room with a one way vent on the outside portion. This worked relatively well.
Finally a good clean before we started processing. We did a ethanol solution on all the walls floors and ceilings and then a soap and water washdown.