https://www.amazon.co.uk/Bio-Ears-Silicone-EarPlugs-Protecti... I use these, they are big enough you can split one plug in half and use them for a few nights so I get a couple of weeks out of a box, own brand ones are no worse, boots in the uk does them at about half the price.

Honestly though they are cheap at 5 times the price for a good nights sleep.