There are 3 main dining plans. Each of them give you credits based on how many nights you are staying in a Disney hotel. Tickets are not relevant.
I can give you the prices for 2014. I guarantee the prices will be higher in 2015, but I can't tell you how much higher they will be.
Quick service plan is $39.64 a night. It gives you 2 quick service meals (entree, dessert and drink), one snack and a refillable mug. You can use the mug for coffee, soda etc in any WDW hotel. It is not used in the parks.
The Plus Dining plan is $58.66 a night. It gives you 1 quick service meal (entree, dessert and drink), 1 table service meal (entree, dessert and drink), one snack and a refillable mug.
Deluxe dining plan is $104.94 a night. It gives you 3 meal credits (appetizer, entree, dessert and drink), 2 snacks and a refillable mug. You can use the credits for a mix of TS and CS, but you won't get your money's worth that way.
Now, you are on a budget. Start looking at menus on this site, allearsnet and wdwinfo. See if you will want a dessert with every meal. If not, the DDP might not save you money. Also look at what you might like to order at different places. If you cost comes to less than the DDP, it might not work for you.
Also read mousesavers.com. They have a lot of useful info on saving money in WDW.
http://www.mousesavers.com/walt-dis...ney-world-meal-snack-drink-discounts-coupons/