So far I've invested in glitter, suspension bases, and bottles--pretty much everything I need to create a bottled glitter topcoat practically from scratch.
I've gotten three types of small bottles (5 ml) from a very reliable supplier--which is the same place I buy my base. I've discovered that for my particular hobby, their glamour base works better than their luster base. I think the glamour base suspends glitter better and more evenly. I also give a big thumbs up to their empty nail polish bottles. They come unassembled, in three parts: bottle, cap, and brush, but it's easy peasy to assemble and fill them. An example of one of the bottles can be seen in my post "Mini White Experiment" from June.
I get larger (.5 oz) bottles from a different supplier. They ship unassembled as well, and are as sturdy and easy to put together as the ones from the other company, the first one I used.
I haven't tried bottles from any other supplier, but I'm always on the lookout for new ones, for variety's sake. I'm quite pleased with the ones I'm using now, though!