How I price my shirts

One of the questions I see posted a lot in the crafting groups online is, "How much do you sell your shirts for?".
And then you get a lot of people that answer and all the answers are different. There is no set amount that you can apply to shirts, generally speaking.
It all depends on a number of factors, how much did you pay for the shirt? how much did you pay for the vinyl? do you want to pay yourself for your time?
I just recently created a pricing guide for my business and thought I'd share with you all and it may work for you or it may not, but here it is...
I have a resale license since I am a retailer and buy wholesale and then resell. As an apparel decorator, I add materials, vinyl designs, etc...to my shirts before I sell them. In fact, I am not even allowed by the agreement I have with my shirt distributor/manufacturer to sell the shirt blank. I am not a t shirt distributor, I am an apparel decorator so I am agreeing to buy the shirt, decorate it and resell it. So check your fine print from the source where you purchase your shirts.
A lot of cost goes into my finished product so how do I come up with my end price? I take the cost of the shirt and then double it. Well, that's what retailers do. They buy wholesale, double it and then resell it so right off, the blank shirt gets doubled. Then there is the cost of shipping, well some add 10%, some add a set amount. I add a set amount. $1. Whatever works for you.
Then I add the cost of my design to the shirt, which is $10. If I sell an htv transfer to someone to press at home on their own shirt, I charge $10. This is for a basic, 1-3 color, reasonably sized (9-11") front or back. I charge more for upgraded vinyl like glitter, foil, more for front and back, highly detailed, lots of colors, etc...
I came up with my own formula for the shirt design, but it is basically $10. If the garment is a high priced one such as a hoodie, then I add only $8 for the design since my profit is higher on the garment alone.
You don't have to follow this exact, you can take what you want and apply it to your business. Everyone runs their businesses differently, but hopefully this will be a starting point for you all.
You have to take into consideration all the things that go into your business, license renewals, fees, materials, vinyl, weeding tools, cutting strips, blades, wear and tear on your machine, your expertise-researching, trying out different materials, shirts, vinyls, and mostly, your time.