My kids (11 yrs and 15 yrs) did a fist dive with these guys at a reasonable rate. The quality of the tuition and attention to detail and safety were very impressive. They came to our hotel after we showed initial interest and let my kids try before we signed up for anything. 
On the day they picked us up and dropped us back to our hotel. My kids loved it so much that they had a follow up dive and went into the bay to a depth of nearly 12 metres, which is as epic for a 15 year old as it is for an 11 year old. I cannot recommend these guys highly enough. There are lots of diving schools in Puerto Del Carmen but I felt totally safe handing my kids over to these guys. The instructors are brilliant.

Visited July 2015
Jason, http://www.tripadvisor.com/ShowUserReviews-g662290-d1382723-r290527383-Manta_Diving_Lanzarote-Puerto_Del_Carmen_Lanzarote_Canary_Islands.html#CHECK_RATES_CONT