https://www.kickstarter.com/projects/1897301425/scorkl-breathe-underwater-with-total-freedom
This new Kickstarter Project is pretty incredible but they are quick to warn that it should not be used by people not trained in scuba diving below depths of 3 meters. With that said at $295 for a Scorkl, scuba tank refill adaptor and pump, this is an affordable alternative to full on scuba gear for short duration shallow dives:
“The Scorkl is safe, easy and for everyone. However, if you are not a trained scuba diver there are restrictions on use and risks to be aware of. Misuse of the Scorkl can be dangerous. Whilst decompression sickness (more commonly known as “the bends”) isn’t much of a risk because of the depth and time restrictions of such a small cylinder, pulmonary damage (chest expansion injury) is nevertheless a risk if a user holds their breath during ascent or ascends too quickly.
Scuba-trained users will be able to use the Scorkl below 3m at their discretion but they too will be warned of the same risks. 
Each Scorkl comes fitted with a pressure gauge so that the user can know how much air remains in the cylinder at any time. 
AIR QUALITY
The Scorkl can be filled either directly from a scuba tank or from our high-pressure hand pump. If filled from a scuba tank that itself has been filled by a commercial compressed air supplier, the air can be assured to be of good quality because of industry supplier standards. These standards are concerned mainly with carbon monoxide, carbon dioxide, oil and water levels. Since the Scorkl hand pump doesn’t have as many working parts as a mechanical dive compressor, and is muscle-powered rather than petrol powered, the risk of contamination from latent carbon monoxide and carbon dioxide is dramatically reduced. This is the same for oil contaminants. Notwithstanding this, each Scorkl pump comes fitted with an air filter which is comprised of the same materials, and performs the same function, as a filter fitted to a mechanical dive compressor. The Scorkl filter should be replaced after fifty refills and extras will be available for purchase after the conclusion of the Kickstarter campaign.
EQUIPMENT STANDARDS, CARE AND MAINTENANCE
The Scorkl cylinder and regulator are made to the same international specifications and standards as normal scuba cylinders and regulators and need to be visually inspected and/or tested as regularly as the guidelines in your country require (some are different). This may be as regularly as every year or every one hundred dives. 
TO PURCHASE GO HERE