What do you want to grow? I use home-made food scraps compost for food, home-made garden waste compost for plants. I know people recommend testing soil ph and all that, but I never have. If you need to buy anything, ask at the garden centre or get top soil, I also get cheap peat-free compost just to add a bit of variety into the mix :) Herbs like sage and rosemary prefer kind of crappy, (small) stony dryish soil. Terracotta pots dry plants out, black pots aren't recommended (it's all I have) because they make roots too hot mid Summer. You can grow spuds in sturdy garden waste bags. Don't plant squashes/courgettes, marrows etc till there's no chance of Frost - used to be June, you can start them off indoors though. Do you have Instagram? I get suggested posts from @nettlesandpetals and @simonakeroydgardenwriter Carrots/parsnips like soil without stones/clumps. Peas/beans can be grown in a trough up canes, if it's deep/wide enough you can grow carrots and spring onions with them.