I started an LLC in Dec 2017. I haven't started making money as of yet, Jan 2018. The LLC is registered in Wy and I'm in CA. Do I add the $2500setup cost on my 2018 taxes

[MelaineC]

No, while you may not have made any profits if you have expenses you may want to file a Schedule C to claim them.  If you do not claim your expense in the year you pay them, you may not be able to deduct them in the future when you do have income.  So add these to your 2017 tax return.  They won't be allowed if you have no income in 2017 to deduct them from.  Instead, they will be carried over to 2018 and deducted then, provided of course you have the income in 2018 to deduct them from.  

Please read the following article to guide your decision; Can I File An Income Tax Return If I Don't Have Any Income?  It will provide you with advice on filing if you have any expenses, such as the cost of your business license.  I am also including here an article on Start-up Business Tax Tips to help as you encounter more start-up questions.