I live in Seattle WA. I am trying to find a store where I can buy vegetable seeds in bulk. Generally I buy from home.depot but it is very expensive. So.please suggest me a store where I can buy seeds in bulk.

The only "bulk" seeds you're going to find in Seattle retail outlets are for things like ground covers and grains. Sky Nursery in North Seattle (it's
actually just over the border in Shoreline) has some
of those. Many online/mail order seed companies sell all kinds of vegetable seed in bulk, and of course the prices that way are
way lower than the single-packet prices. I would think Home Depot's prices to be about the lowest available for normal quantities of seed.

I'm not pushing Wilhite Seed, just using them as a pricing example for a highly reliable seed source. Here's the list for Israeli Melon.

Note the really big jumps in savings from 1/16 to 1 ounce and up to 4 ounces. It slows down a bit after that, but there's still a good benefit going up to one pound, assuming you can use that much. These are big seeds, but there are still 1,200 per ounce and 19,200 per pound.

The proportional savings are more modest after that. But still real money if, again, you can use the quantity. And always consider each dealer's shipping costs.

1/16 OZ $2.20
1 OZ $3.85
1/4 LB $4.80
1 LB $14.80
5 LB $62.80
25 LB $282.50
50 LB $508.50

A good reliable source for bulk seed specific to the PNW is Territorial Seed, out of Oregon. They sell locally in most feed stores, and their online or paper catalog is chuck-ful of useful growing information. In addition to individual packets of seed (a bit on the spendy side), they also offer bulk rates which are much less expensive. Years ago, we used to get together with fellow gardeners and 'pool' a large order then split it out for savings.

https://territorialseed.com

Another is www.outsidepride.com in Oregon. I have purchased their grass seeds and flower seeds

Yes, I like Territorial Seed. Also Seed Savers Exchange for things in their niche. I think bulk for them is 8 ounces.

I ordered from Morgan County seeds for wholesale, but I get individual packets and they are very reasonable.