My guess is a
I can show you the world while staying in place,
From beaches to mountains, just keep up with my pace.
Paintings of various sceneries exist, but there are so many that its impossible to process them all
I also show beauties, like gemstones and more,
Or stuck in museums, while you take a tour.
Pictures of items, and art museums.
Sometimes I’m priceless, when I am old,
It takes a while for me to be sold.
Classic art can go for millions of dollars, and auctions are hyped up and bidders fight etc
When I seem broken, I still have a meaning,
Like the old tower; Why is it still leaning?
Lots of artworks retain their message (and some messages are even strengthened) when they "break" or some outside force (time or censorship or etc) tries to wear them down.
Some people like me for beauty and pleasure,
Others look at me like I am a treasure.
A painting can be enjoyed because it is beautiful, or because it holds other meaning. It can also be treasured and revered like a coat of arms or a national flag.
Not ticklish refers to the paintbrush swirling around, "tickling" the canvas (which does not laugh ofc)