I was just issued a design patent 10/27/15 (application filed 2/13). The problem is that in the last 2.5 years since I applied for it, many small vendors have taken my design and are selling it online. Even after I posted Patent Pending and contacted a few of them personally. Is there any weight to sending an email myself along with a copy of my patent to these vendors asking them to stop selling my design? I would like to try this approach before giving my lawyer money to send formal letters. Thank you.
Do not try the informal approach; go to an attorney for advice.
First, I am not an attorney. However, if you send a letter asserting patent rights (which is basically threatening to sue them if they don't take a license or cease and desist infringing your patent) you may risk triggering a lawsuit for a declaratory judgment to resolve any outstanding allegations, which will likely be on their home turf - not yours - and you will have to fight it out with them in a far-away court or give up your claim of infringement.
Also, unless you have experience with patents and infringement, just because something is "obviously" infringing to you doesn't necessarily mean that the courts will see it that way.
You need legal counsel. Good luck.
Aldo is correct. Don't send such letters without the assistance of an attorney. It's easy to get sucked into a declaratory judgment (DJ) lawsuit, which is extremely expensive.
Also, the legal threshold that allows a letter recipient to file a DJ action is relatively low. For example, even if you don't specifically threaten a lawsuit or assert infringement, you can still be slapped with a DJ action. Even seemingly "friendly" letters can be grounds for a lawsuit.
Talk with a patent litigation attorney to plan an enforcement strategy.