Simple can be effective
You do not need bags of kit to have a bit of fun.
Use what ever is available in front of you at the time.
Low cost, you already have it.
Fun exploring new things.
Recycling is good.
Options are not always available when you want them.
Uncertainty of the performance in what you choose to try.
I often mention about DIY toys and recycling but I wanted to touch on the side of with all of these things available to us, simple is often fun. You do not need bags of kit and be the most uber of what you do as at the end of the day its between you and your partner / who you play with and what works best for all involved in the dynamic.
On my desk in front of me is the first item that came to mind for what I could use for something simple on my slave girl Charlie. They are office bull dog clips she bought a few days ago for putting in the kitchen for various notes and letters from the postman with appointments and so forth. They worked out at two pound for the four and are of a stainless steel material with a stressed piece of metal rather than a spring which makes them easy to clean and ideal for a kitchen.
Charlie is rather masochistic therefore the thought of trying these clamps was a simple yes please and she got out the part of her body for the job..
Moments later clip clip and shes smiling. Brand new never used clip and gave it a go. Turns out they hold on really well, have a strong firm grip and the handy holes can be used for attaching various weights or holes. Not bad for two pound and a random adventure in trying something new.
What I would say is give a go at using something completely random for something it was not intended for. You may find its useless, you may find it fun but either way its a fun way to explore something new and engage with each other. It may even become a topic of conversation at a later date.
Here are a few common house hold items you may have around your home that you could consider trying if you are having difficulty thinking of something.
Onions and ginger.
A tray of lego.
A sock stuffed with three or four folded up socks.
Put the rear end of a battery electric shaver in a condom and see how much is vibrates.
Plenty more simple ways to have fun have a look.