The Deco scooter is a cheap old one. Vintage 2007-9 or thereabouts - they closed them out on Woot for $119 4-5 years ago. Assuming the battery still holds a charge and you have the charger $50 is probably
very optimistic. I don't even think it's a dive scooter but more a Seadoo knock-off for towing kids around on the surface.
Amazon.com : Deco Stingray Seascooter Blue Those cheap scooters don't have the thrust/motor to haul a diver around.
The Ikelite Camera case is going to be hard to price because Ikelite didn't generally put model #'s on them until fairly recently. It's a video camera case assuming the composite cable shown in the photo goes with it. Hard to tell from your photo but is there a camera inside it? - that's how you ID them, match the camera model # to a housing list on their website - or they will for a fee if you send it to them. New their housings generally ran about $ 900-1200 but they're model specific due to control placement so unless you have the camera there's not going to be much interest in an older one.
Many newer video housings are marked with the Ikelite product number (which takes the form #### or ####.##). Please have the product number ready and contact us to find out which camcorders are supported by that product. Older video housings that do not reference their product number must be returned for identification. There is a charge for this service.
Ikelite | FAQ About Housings
The other case looks like a complete camera kit. The strobe could be a Sea&Sea YS-series - hard to tell due to the distance the photo is taken from. The camera looks somewhat older and is possibly a different mfr.
Aeris Compumasks sold new for around $1000/1100 several years ago. Aeris recently was absorbed back into Oceanic who I believe still sells the mask. Right b4 that happened they were selling new w/warranty for around $800.
Post a pic of the BC if it doesn't have a name on it. Depending on the make/model it could be worth a couple hundred used. The fins should have a name on them - match them here since they list MSRP.
Diving Fins, SCUBA Fins, SCUBA Flippers | Aqua Lung
If the tanks are steel, post them on your local craigslist, shipping tanks is expensive.
No one is likely to buy that gear as a lot so your best option is to break each item down separately (except for the camera gear) and list it in our classifieds once it's been properly ID'd.
If those camera/scooter cases are Pelican or another known-brand - at that size they sell new for several hundred dollars.