Since you are charging people, hopefully, you have a legally registered business there in Michigan, you're keeping good financial records, you're collecting and forwarding state sales taxes, paying use taxes, self-employment taxes, have liability insurance, etc:
http://www.michigan.gov/documents/business/Guide_to_Starting_a_Small_Business_271487_7.pdf
Don't confuse gross revenue with profit.
If a client pays you $100 to $150 for a session and product, you have to deduct your business costs and cost of goods before you can determine if you made a profit, or didn't make a profit.
Whatever salary you pay yourself is a business expense. You probably don't realize it yet, but you have many other business expenses.
Most retail photography businesses, that do not have a studio, produce income at a rate of about 25% of revenue.
You mentioned $20 an hour as the rate for your time.
If you were paid $150 to do a shoot, and editing, that took 3 hours total, $60 of the $150 paid for your time.
That $150 also pays for the time you spent with the customer arranging the booking and doing the post shoot/editing customer contact. Lets call that another hour. So the first $80 pays for your time. By the time you subtract your other business expenses it's likely you lost money on the shoot.
75% of a retail photographers time is spent doing business tasks. The remaining 25% of a retail photographers time is spend doing photography for customers.
In other words, you have to charge so what your customers pay you covers 100 % of your time engaged with your business, not just for the shooting and editing time you spend on a customers session.
Print markup needs to be more in the line of 200% to 300%, at least.
Small prints get marked up a lot more than large prints get marked up.
For large prints I charged by the square inch.
I sold 4x5 chromogenic prints with a matte finish for $40 and 8x10 chromogenic prints with a matte finish for $75.
A 16 x 20 chromogenic print with a matte finish was $160 (320 square inches x $0.50 per square inch).
If the client wanted a lustre finish on a print, a print on metallic paper, a Gicleé print (high quality inkjet print), a canvas, a print on metal or acrylic, the more costly the print.
Mounting, matting and framing was of course extra too.
Several times over the years I have made posts that show the math that demonstrates a well run full time retail photography business needs an average sale of about $400 just to break even (no profit, but business expenses are covered). That assumes the photographer is willing to live on an income that is barely above the poverty line.
The average session sales goal I shot for was $2000 per session.
I expected to shoot 3 days a week out of a 6 day work week, and since retail photography can be a seasonal business I only expected to shoot about 40 weeks per year.
The other 3 (long) days were totally devoted to doing business marketing/promotion/maintenance tasks.