The LEGO company has recently launched a service called "The Minifigure Factory" which allows you to create custom minifigure. It is an online service, but it is quite difficult to access.
First, you need to use the search function on the LEGO website. Just type in "factory" or "minifigure factory", and you’ll be able to see this service as one of the first results. Click it, and then you’ll see that the minifigure factory is supposedly not ready yet. This is not true! In order to bypass this, simply scroll down to the bottom of the LEGO website, click on “cookie settings” and then click “accept all”. After that, simply refresh the page, and now you have complete access to The Minifigure Factory.
While this service is still technically in Beta, you can still order your custom minifigures right now, and they will arrive at your doorstep pretty quickly! I already got my custom minifigure! Once you click on “customize your minifigure” you can select one of ten minifigure faces. Unfortunately you cannot make custom faces. Then, you can select one of twenty different hairstyles! The real fun begins with your ability to personalize the minifigure’s torso! You can select one of a ton of different torso designs, and you can also add some clip art anywhere on the torso, whether its on the front or the back. My favorite part about the minifigure factory is the ability to add custom text onto the torsos. That’s right, you can put any word or phrase onto the minifigure’s torso, and this is absolutely incredible! You can put your username, brand name, or really anything else onto the minifigure’s torso! Personally, one of my favorite decorations for the torso is a dinosaur! It is so cute, and adds so much life to your minifigure! Then, you can select one of 8 different leg pieces, and one of two different dress elements. Unfortunately have no printing on them and you are only choosing between the different colors. There is zero difference in the legs besides their color. Finally, you can select one of 30 different accessories for your minifigure! Personally, my favorites are the trident as well as the dog.
Then, simply check out, and wait a few days for your custom minifigure to arrive in the mail! You will be quite satisfied with the result! I just wish that we had the ability to add custom images onto the minifigures, since that would open up a whole new world of possibilities, and it seems quite limited now.
There are also several services ran by LEGO fans that specialize in printing their own designs onto existing LEGO pieces. However, most of these do not offer personalization, they just offer unique prints that the LEGO company never made. My advice to you is to ensure that these services actually use genuine LEGO pieces.
However if you are looking to personalize Lego Merchandise such as luggage, backpacks or storage items, you have lots of choices. For example Personalization Mall does personalization of Lego containers and Lego pencil cases. Lego pencil cases are on sale for $13.99 at Personalization Mall and they do encourage you to use coupons, like 20% off below.