Here are several places within walking distance of campus to get a quick treat during class breaks, depending on how much time the break is.
If you have a 5-minute break:
The two best places for a 5-minute break are the school vending machines and Tamales Jovita across the street. The vending machines vary in price, selection, and reliability, but most things are under two dollars. Tamales Jovita is directly across from the 155 building. One can get two tamales for four dollars or a meal with rice and beans for six dollars. Without a line, you could easily get there and back to class in five minutes. They also allow orders through Facebook Messenger to have orders prepared before you arrive. It is a great option for a short break, if you need something more filling than what is in the vending machine.
If you have a 10-15 minute break:
The best places to go for a ten-minute break is Starbucks, Cute Cakes, or Ritz Delights. If you decide to make a Starbucks run, order online, so that the drink will be ready when you get there. If you wait to order, it would probably be best to give yourself 15 minutes. Cute Cakes is another great coffee spot, but sometimes they have a bit of a wait for coffee. If you are getting coffee, it might be good to give yourself 15 minutes. 10 minutes is the perfect amount of time for something like lemonade or a bakery treat. The safest bet for a 10 minute break is Ritz Delights. This small shop across the street from the 155 building sells ice cream, slushes, boba tea, and various snacks. Most items there are five dollars or less.
If you have a 20-minute break:
If you happen to get one of these rare breaks, the best option is 7/11. Walk out of the 155 building onto Grand, turn right, and walk a couple blocks down. 7/11 has various drinks, snacks, and candy. In addition to its wider selection, it also has pretty cheap prices, plus you get a scenic route through Downtown Escondido.