Tip #3 "Second-hand first"
This tip is very simple, but maybe feels hard in the beginning, depending on the facilites in your country:
If you think of items that you need and want to buy, ALWAYS first look second hand! There are several platforms online, both national and international, where people exchange stuff for a low bid or even free. And in many countries, you will even find smaller and and bigger thrift stores, where you can find these items. Of course, you still need to check the consdition and quality. But that is what you would do on a "regular" shopping trip anyways, right?
Example: Personally, I find it fun to set a date once in a while for searching 3-5 thrift stores in my area for anything I am still missing. (See list from tipp #1.) I keep it short, search focused for item X and then at the end of the day buy it or leave it. In my opinion, that is about the same effort, or less, when doing a "regular" shopping trip.
TL;DR: Search for your wanted items in second-hand stores or online marketplaces. Often you find what you need, in still good condition and cheaper. Also you give these items a longer life. And the effort is similar/lower to "new shopping" if you do it focused.
A big frustration i find on this area is Facebook marketplace has dominated secondhand listings. I hate FB. Even more so as it’s gone down the eBay route of marketplace tat over used products.
Leading to second point. Marketplaces like eBay searches are so hard to find used or local items. I have to filter and faff.
Any suggestions or alternative markets uk based?
Here in France (Paris) I find a lot of used stuff looking at flee markets, yard sales (vide grenier, we call them). I never use Facebook Marketplace. Online, I use the French website leboncoin.com that supposedly focuses on letting individuals sell used stuff to other individuals (unlike Ebay, there is no biding). There should be a UK equivalent. Or Ebay, but it's not what it was once and barely use it nowadays... says I, less than 24 hours after I purchased 2 items from 2 different sellers ;)
I do like car boot sales and second hand shops. There are just somethings that are better suited to classified, an extendable dining table for example, or time sensitive items.
There is gumtree which is very trashy. I miss when eBay felt local and primarily for selling/buying used.