Rest in Puerto del Carmen is relatively inexpensive. The main expenses of travelers are air tickets (from 350 EUR round trip) and accommodation (from 25 to 300 EUR per day). Prices in Lanzarote are much lower than in mainland Spain (up to 30% lower on perfumes, electronics, tobacco products, wines) due to the absence of fees on imported goods.
Average check in restaurants, coastal cafes - 20-30 EUR for "sea" menu or traditional sandwiches, steaks, pizza.
Of course, the budget for a trip to Puerto del Carmen should include excursions - there really is a lot to see in these places - as well as unforeseen expenses.