I would check thrift shops regularly to see if you can find an older sewing machine cabinet that you can adapt to your machine. Old sewing machine cabinets do not sell well in thrift shops, so if you keep up the hunt you should be able to find something suitable for very few dollars. You might even need to buy one with the machine inside, then take out the machine and donate it back to the thrift shop! Be sure to measure your machine first and carry a measuring tape in your purse; you want to make sure that your machine will fit. Also, if you intend to close up the cabinet when not in use, you will probably have to drill new holes to bolt the machine to the base (assuming you have a machine that can be bolted.
All of the new cabinets I have seen are extremely expensive for what you get.