I have a bunch of anal toys, and I like them, but none of them are vibrating. I live with others, so I was hesitant to buy anything vibrating.
Are there any reasonably cheap anal toys (under £40) that are reliable, and most important, quiet, maybe even enough so you could be wearing it and no one could tell if it was vibrating if they were a couple feet away. I don’t want any chance of someone hearing it, because I just won’t be able to enjoy myself.
From my experience I don’t think you will find anything quiet enough that is could be vibrating and someone being close to you definitely won’t hear it. There is always a possibility someone may hear it unless there’s is constant noise in the room such as loud music.
As for the toy itself you would probably want one with a remote so it can be easily turned off if wearing it in public is the goal. I can’t think of one below £40 but would suggest this Butt plug if you are able to stretch the budget. It’s on offer and with the forum discount you can get it for £55.99.
Edit - I forgot toys have a low vibration setting 
but @AJSTAR just reminded me of that so I guess lowest setting it would be possible.
I actually bought this toy for anal play and on its lowest setting I’d say you can happily use it and no one will hear it!
If @AJSTAR recommends that egg then I’d consider that. Personally I’ve never found anything that provided a satisfying vibration and was silent.
What you could consider is e-stim. That can provide a whole load of sensations and is most definitely silent.
E-stim is great but can be quite the tangle with wires!
The egg though is a real eye opening surprise to give a try 
