If you go to http://www.lcipaper.com/wholesale-envelopes.html they can sell you envelopes in bulk. They will allow you to get a discount like the more you buy the more you save.
http://www.actionenvelope.com/ is a great website for buying bulk shipping envelopes. Buying in bulk usually results in reduced prices and consistent quality.
Prices for windowed envelopes will vary depending on the size and amount of envelopes you are looking for. A good start would be large office supply companies like office Max or staples. These stores generally provide a discount to business owners who buy in bulk.
You can find shipping envelopes at your local post office. Another good place to look would be your local office supply house as most do carry shipping envelopes.
Best office chair for buying in bulk would be the smaller task office chair. They may not offer as much comfort, but would be affordable for buying in bulk.
There are none that I could find that specifically offered a bulk buying discount. However, it never hurts to call a vendor and ask directly for a discount if you are going to buy in bulk, they will typically accomodate you in some way.
Most office suppliers will offer a discount depending on what quantity of goods the customer is buying. The amount of discount can vary from store to store, though it is the usually same discount throughout a large chain of stores.
The companies VictorEnvelope and ThePaperMillStore specialize in producing bulk envelopes. Both websites produce a great variety of envelopes, which can be found on their websites.
It means purchasing a large amount of one item and usually with a discount. For example buying 1000 of the same book is a bulk purchase.
You can get bulk poly envelopes from most big box office stores, such as Office Max, Office Depot, and Staples.
It might be possible to get wholesale janitorial supplies at a discount. It really depends on the company you are buying from and their policies. Sometimes buying in bulk yields a discount as does being a repeat customer. http://www.wholesalejanitorialsupply.com/
Cheap square envelopes can be found at stationery stores (such as Grand and Toy), in stationery catalogues, through local discount stationery suppliers and through purchasing the envelopes in bulk. Often, envelope manufacturers will have information on their products (along with discounts and promotions they offer).
You can get bulk buy discounts if you are planning to buy in bulk from the wholesaler selling Christmas ornaments as most retailers give this as a common discount to bulk buying customers.