Blending your own would be fun. One of my friends did this for years and he experimented on me to get my opinions of the flavors. A coffee cart is good business, BUT you do need to be sure you have the right pedestrian traffic volumes to make it pay well.

As a ROUGH rule 2% of traffic will buy. Do a 'customer count' and try to find a happy average figure for the daily traffic at your preferred location. That should tell you approximately how many coffees you will sell per day. Get a spreadsheet and work out your expected daily takings and from there, your net.

Find a coffee cart that is operating somewhere and count customers walking by and those buying. It's easy if you have a hand counter. Click it for the walking by, and mentally count the buyers.

You should reasonably expect the same buyer percentage figure for your business.

You could try either adding juices to the stand or selling only juices.

I have seen orange juice sellers in VERY BUSY places gross over $10,000 weekly. BUT the first one I saw was in a VERY BUSY place. I did a customer count and was most surprised to see the figures.

Don't think in terms of 'a coffee cart' (CC). If the first one goes right, then get a second CC in another spot. But long before you even think of getting a second CC, scout out a suitable spot using the customer counting technique.

You might want to have donuts and the other usual stuff too.

Save your money and pick up a second-hand CC.

Let us know how you go with it.