I sold $1200 on Mecari. They did not send me a 1099k because its below the federal threshold. I live in MD and the threshold is $600. Should they give me a 1099K?

Maryland does have a lower threshold.  

However, you are required to report income earned worldwide whether you receive an IRS form 1099-K or not.

If you are reporting personal item sales in TurboTax Online, you may follow these steps:

• Down the left side of the screen, click on Tax Home.
• Click on the down arrow to the right of Review.
• Click on the blue band labeled Review.
• Down the left side of the screen, click Federal.
• Down the left side of the screen, click Wages & Income.
• Scroll down to Other Common Income click on the dropdown menu.
• Click Start/Revisit to the right of Form 1099-K.
• At the screen Did you get a 1099-K?, select Yes.
• At the screen How would you like to upload your 1099-K? click Type it in myself. 
• At the screen Which type of income is your 1099-K for, select the button for Personal item sales.  Click Continue.
• At the screen Let's get the info from your 1099-K, enter the information.     
• If necessary, select the box "This amount in box 1a is too high or includes some personal transactions."
• Click Continue.
• At the screen Personal Item Sales, you are told that further information will need to be entered.  Learn More provides detailed information for the next steps.  Click Continue.
• At the screen Your 1099-K summary, notice that the income relates to ‘Personal Items’.  Click Done.
• At the screen Your income and expenses, scroll down to Investments and Savings (1099-B, 1099-K….).  Click the down arrow.
• To the right of Stocks, Cryptocurrency, Mutual Funds, Bonds, Other (1099-B), select Start/Revisit.
• At this screen, you will be asked to Review the Personal item sales (1099-K).  Click Review.
• At the screen Now, enter one sale…., answer questions about the personal item sale.  Click Continue.
• At the screen, Let us know if any of these situations apply to this sale, sales expenses may be recorded.

The entry will be reported:

• on Schedule D of the Federal 1040 tax return, and 
• on line 7 of the Federal 1040 tax return.

Capital loss for a personal item sale reports $0 capital gain on line 7 of the Federal 1040 tax return.