I roasted my veggies in the oven; sweet red peppers, tomatoes, and scallions all tossed in in olive oil and left in a hot oven for about 45 minutes.
Once I pulled the veggies out of the oven I left them cool a bit and then chopped all the veggies up (pulling the seeds and membranes out of the peppers.) The veggies were mixed with garlic, olive oil, and vinegar and could either be served hot right away or cold later. I took mine for lunch so I ate them cold, and wasn't thrilled at all.
Someone else might love this, but it's not for me.
tomato -- $1.83
red pepper -- $5.98
callions -- $.89
Total Cost of Escalivada: $8.70