"Learning the notes on the guitar is a pain", said every guitar student I've ever met.
Yes, it's not the funnest part of learning guitar, but it's one of those things that you really need to do as you progress as a guitarist. Without learning the notes on the fretboard, you eventually get stuck at a certain level, and your progress will be impeded. This is especially true for people who want to learn improvisation.
While there are a few methods that make learning the notes a bit easier, like these 5 tips, and understanding the tonal relationship between the guitar strings, there are a few products that can help you learn those notes.
Don't Fret Note Map
I found this note map as I was searching for a way to help a student, who was desperate for some assistance in learning soloing. He was having a hard time remembering where each note was.
This is how I came across the Don't Fret Note Map.
It's a very simple, but very useful invention tailored for beginner guitarists. It's basically a set of vinyl see through stickers, which you can place on your fretboard. It does not use any adhesives, so it is safe to put on your guitar.
You basically wrap the vinyl around the neck, it'll form a smooth surface on the fretboard, and sticks to itself on the back of the neck. Here are the detailed steps of how you would apply it.
I wouldn't recommend keeping the vinyl wrapped around your guitar for extended periods though, but it's easy enough to put on and take off any time, so don't be lazy.
The product costs $10 + shipping fees, so it's pretty cheap and all the more useful, if you are struggling with learning those notes.