Sundried tomatoes can be heinously expensive if you buy them by the jar. I’ve discovered that it’s far cheaper to buy a bag of them (you may be able to get them in a bulk section at the shops). Then, all you need to do is drop them in a pot of boiling water for a few minutes, and then let them cool.
If you can wrestle a mason jar from a hipster, then use one of those, or just any old glass jar. Put the tomatoes in the jar and cover them with a generous amount of olive oil. Depending on what you like, you can also add some chilli flakes or herbs. These store really well in the fridge and make an excellent pizza topping.