If you can’t find a pad big enough for your bed, you can combine 2 smaller pads. Non-slip mattress pads are very thin, so you shouldn’t notice a difference in feeling when you sleep on the new bed setup.
Some gripping pads are sold as multi-use for both mattresses and area rugs, so it may not necessarily be a cheaper alternative, but it’s worth shopping around if you want to save a few bucks!
Make sure to use “hook” and “loop” pieces of velcro opposite of each other, or the velcro won’t stick! You could also try using double-sided carpet tape in the same way if you can’t find velcro strips.
This is a good way to temporarily stop sliding, however you will probably have to keep adjusting whatever you wedge in between the mattress and frame, so it is not a great permanent solution.
A bed frame that has both a headboard and a footboard can help reduce sliding as well.
1-sided mattresses can also be more comfortable than 2-sided mattresses because they are built bottom-up for maximum comfort on the sleeping surface.
The sheet suspenders should look like an “X” underneath the mattress.
You can also use safety pins to hold the fitted bottom sheet in place which will keep the mattress topper more stable.
Note that if you use spray adhesive, there will be some residue left on the mattress if you ever want to rip off the topper. Duct tape can leave some residue on the mattress too if it is left on for a long time.
The more plush the rug is, the more traction the bed frame will have.
You can get furniture feet at most furniture stores or home improvement centers.
The rubber liner you want to get is the kind used to line cabinets and keep things like glasses from sliding around.