Self Employment Taxes

[Jacob Plocinski]

I work full-time and have a side gig as a Realtor. I will probably only turn over about 6-10 transactions a year, equating to $14,000 to $24,000 gross additional income. I've read through the Self-Employment tax documents. In future preparation should I be making the quarterly payments on that estimation? Or wait until near the end of the quarter and make payments based on the actual income I've made. 

What type of penalties could I expect if I wait until end of year to complete tax computation? Thanks for you help in advance.