To assess type, nutrient profile and cost of food items sold by informal vendors to learners; and to determine nutrient content of corn-based processed snacks frequently sold.

Cross-sectional survey.

Quintile 1 to 3 schools (n 36) randomly selected from six education districts; Eastern Cape, South Africa.

Informal food vendors (n 92) selling inside or immediately outside the school premises.

Food items sold at most schools were corn-based processed snacks (94 % of schools), sweets (89 %), lollipops (72 %) and biscuits (62 %). Based on the South African Nutrient Profiling model, none of these foods were profiled as healthy. Foods less commonly sold were fruits (28 % of schools) and animal-source foods; these foods were profiled as healthy. Mean (sd) energy cost (per 418 kJ (100 kcal)) was highest for animal-source foods (R2·95 (1·16)) and lowest for bread and vetkoek (R0·76 (0·21)), snacks (R0·76 (0·30)) and confectionery products (R0·70 (0·28)). The nutrient profiling score was inversely related to the energy cost of the food item (r = −0·562, P = 0·010). Compared with brand-name corn-based processed snacks, non-branded snacks had lower energy (2177 v. 2061 kJ; P = 0·031) content per 100 g. None of the brand-name samples contained sucrose; six of the nine non-branded samples contained sucrose, ranging from 4·4 to 6·2 g/100 g.

Foods mostly sold were unhealthy options, with the healthier food items being more expensive sources of energy.