1.) Is it beneficial for someone to buy into the
DVC if they just go to WDW? I mean if I buy into the DVC I will still have to buy tickets and everything else. Our last trip cost us around $1500, if I took a trip every year which we have and I bought into the DVC we'd have paid around $1452 just in yearly payments and the additional $500 or so in taxes and maintenance cost. Not including tickets and dinning plan.
First, good luck deciding!

I'm a researcher and a numbers cruncher, so it took DH and I a while to decide. After I crunched the numbers multiple times over, we decided to purchase resale, and it's been totally worth it. We joined in 2007, and we've already recouped the buy-in cost. In other words, had we taken the same trips and stayed in the same locations in the same size rooms, we would have paid the same amount as our buy-in price + annual dues. So moving forward, if the total of our annual trips (rack rates minus some discount) exceeds our maintenance fees (and there's no doubt they will), we're actually ahead. To give you an example, we are staying in a 2 bedroom 12/22 - 12/30 at Christmas. If we paid rack rates and tax, that same room would have cost us over $10,500! Even if you could get a 25% discount over the holidays, that's still around $8K. That's almost triple my MFs. If we decide to sell our contracts tomorrow and get anything out of them, it would even be a better deal! If we sell them for nothing, we have at least broken even.
DVC isn't for everyone, but it's worked out really well for us. Do your homework, as if you're planning on using your points for stays at WDW or trades through RCI, resale is a great option (much, much cheaper). If you plan to go on cruises with your points or stay at other Disney hotels (e.g., Poly), you'll want to consider buying direct, as resales do have some limitations.
Lastly, going to WDW isn't cheap, even if you own. You still have tickets, food, etc. One thing buying has allowed us to do is save some money by eating meals in our room. We always get a 1 or 2 bedroom, so we have a full kitchen. We always eat breakfast in, and usually cook a couple of times during our stay. With DVC, we vacation differently, because we know we'll be back. Some trips (generally 7 - 10 days) we don't visit all of the parks, and have several "pool days." We have found we LOVE the resorts, and just enjoy spending some time there. One other thing to consider...we like to resort hop among the DVC resorts. This keeps WDW fresh, and each vacation offers a different experience. Sure, we have our favorites, but my favorites are different from DH's, so it's a good thing we hop! Otherwise, I book the reservations!
2.) Also I am wondering has anyone bought season passes, and if so did they give you a discount for being a DVC member?
Yes, we just purchased them last visit. We bought the theme park APs (not the water park/fun premium APs), and we saved ~ $100 per ticket. As others have said, this is a perk and could go away at any time. The other thing buying an AP currently allows you to do (another perk) is purchase a "Tables in Wonderland" discount card for around $75. With the TIW card, you get 20% off most restaurants on property for a year. The card discount basically covers the tip (20% off, 18% - 20% gratuity).
Here are the prices/savings on the passes:
Ages 10+ - Annual Pass
$419 - new pass ($100 off reg price)
$374 - renewal ($145 off reg price)
Ages 3-9 - Annual Pass
$386 - new pass ($92 off reg price)
$345 - renewal ($133 off reg price)
Ages 10+ - Premium Annual Pass
$524 - new pass ($125 off reg price)
$484 - renewal ($165 off reg price)
Ages 3-9 - Premium Annual Pass
$483 - new pass ($115 off reg price)
$446 - renewal ($152 off reg price)