This may be common knowledge, but I thought I'd mention it anyway.
My local Lowe's (and I assume all the others across the country) will order anything from Grainger Supply or McMaster-Carr for me; the items are shipped to the Lowe's store where I pick them up.
Pluses: no shipping costs. No price break for McMaster-Carr, but the Grainger prices are Lowe's negotiated prices, so may be lower than the Grainger web site (or local Grainger store). Lowe's will price match if you ask.
Minuses: waiting for the Lowe's truck to get to the store. Paying sales tax. Driving to the store for the product rather than home delivery.
I just go to the 'professional' desk (over by the lumber area) and give them my item numbers and quantity.
Hope this helps anyone who doesn't want to pay freight for large/heavy items that might pack a big shipping charge.