You don't need a Minelab to recover all the goodies at the beach. Just like you don't need a Caddy to drive anywhere. There are cheaper detectors out there too, but waterproof ones are all more expensive.
If you aren't going in the water nor get it wet, a good land detector with a saltwater mode will do. If you stay out of the wet sand, you can use the hot Garrett ACE 250 or one of the Tesoro hot models. The ACE 250 can be had for under $200.00.
Sure you can go cheap for just a few trips down a year, but what if the Treasure Hunting bug bites you as it did the rest of us and you wanna use it at the local park and woods. You'll then have wasted the money on the lower bargin jobbie you bought online.
Just trying to save you some grief.
Good Luck,
Sandman