Here is a list of a few quality local commercial printers that I have worked with who do great printing:
Poster Printers in Brooklyn, NY - speak to Elliot and tell him Clovia sent you
Elliot's email: email@example.com 718-451-1790
www.theposterprinters.com brochures, menus, posters, signage
Printing Factory, sister company in Brooklyn; marketing materials
Southbridge Press in Manhattan - speak to Mitch and tell him Clovia sent you
Mitch's Email: firstname.lastname@example.org 212-233-4047
brochures, menus, marketing materials, stationery and invitations
and my favorite one in South Florida who gives the lowest prices:
K2 Graphics - speak to Dave or Bob and tell them Clovia sent you
Dave's Email: Dave@K2GraphicServices.com 800-480-8650
There are many others in Manhattan, but who are more expensive and only do upscale printing such as:
Museum Press - speak to Yan and tell her Clovia sent you
Yan's Email: email@example.com 212-933-4007
Tips on how to work with one: Contact the reps above and ask for a quote and tell them that you are a designer so that you can get the broker break. You should know about your job in advance. Include all specs such as client/company name, type of project, size W x L, 4/4 or 4/1 or 4/0 (colors), folding - include folded dimensions, bleed, weight and type of paper (i.e. 100# gloss coated text), and delivery zip code for a shipping estimate. Also include if the client needs mailing services or lists (which K2 provides). Then ask for printed samples so that you can show your client the quality and paper material that he/she can expect.
When you receive the quote, that should be the broker break price that you can add your markup to charge your client. Just don't let the client know your markup. Communication with the printer is confidential apart from the client's knowledge. I have both asked my clients to pay the printer separately and also have paid printing costs upfront myself, which I get reimbursed for.
Enjoy getting your artwork in print!