Your base price means that you need to charge at least £20 for the parts alone.
If you get quicker and can bulk buy the parts cheaper then get quicker at making them you could prove them properly:
Parts x 2, including any wrapping, price tags etc
Time for making at at least £10/ hour, include design time
Portion of any time money spent advertising, social media etc again all at £10/hour minimum
Delivery charges etc
Any less and you would be underpricing your time and effort. You'd also be a 'hobby seller' which means you'd be undercutting people who make a living from making.
It's hobbyists that lead to the low prices you have been quoted here. Some people don't value hand made over mass made and won't pay the money that is needed for a maker to do anything other than break even.
It's a perennial problem for makers. I have been called greedy and money grabbing for some of my prices. One of a kind, hand made pieces and, if I listened to the cheapskates, I'd sell at cost and still be called greedy. It's worse for me sometimes as my art is made from reclaimed materials, which I, apparently, should give away for free!
So, before you start to do this think about what you want out of it.
Personally I'd pay £30 for one of your wreaths. So you'd have to get both your costs and time down by at least 50%