In today's materialistic world, we're always led to believe that bigger is better. Why have small when you can have medium; why have medium when you can have large; why have large when you can go supersize. Some things are better the bigger they are, but is it the same with crystals?
The easy answer is no, whatever size your crystal is it will work just the same!
Each crystal has its own type and strength of energy. Howlite, for example, is a very calming stone with a gentle energy whilst even the tiniest piece of Moldavite has incredible power. Many people can feel the energy rippling through their body.
When you're buying online it can be difficult to tell the size of the crystal you're buying, even when the size & weight are shown. It can be difficult to imagine exactly how it will look. What's more important is how it feels. What energy are you getting from it? Does it make you feel the way you wanted to (after you've cleansed it and programmed it, of course)?
You may be tempted to spend more on a bigger crystal but that might not be necessary. Think how you want to use the crystal. If you're going to be carrying it round with you, then a tumbled stone would be perfect, but it wouldn't look as good on your mantelpiece!
If you're unsure about what type or size of stone to choose, we're always happy to give help & advice.