Re: printing and dropshipping
There are some excellent printers out there that will scan and print 12"x17" art if you want to do those yourself without spending more than $240 on the printer. There are professional grade pigmented inks available that cost a fraction of what you will pay for the factory inks. One example is the Epson Workforce WF-7610. It will print very close to the quality of my $675 Canon Pro-10 13x19 printer, even though only has red, cyan, yellow and black inks where the Pro-10 has 10 different cartridges including photo black, matte black, gray and a clear optimizer / gloss enhancer.
If you are selling a lot of poster sized prints, you might consider a large format printer, new or used rather than giving a large portion of your sale to the printing service. They are expensive, so do the math first. If you go used, sticking to HP and Canon in the 24" and wider printers will be a safer move since the heads on those clog and fail less frequently.