If you put all the parts on a wishlist and then buy locally, the shipping cost will generally be only a few dollars each.

Also, I don’t really agree with the notion that bigger stores are more expensive, it really just depends on the store. Here in Canada there’s like three stores that are ludicrously expensive, and all the rest seem about the same.

My sorting works as follows:

• There are four sizes of transparent boxes: About 4.5 liters, 9 liters, 18 liters and 36 liters.
• Some colors I have so little of that all pieces fit into a small box, often just unsorted like “Bright Light Yellow” - although there is one part of which I actually have a bag of that makes up 80% of that color.
• Some colors have more parts, so I have a 9/18/36 liter box with bags of all parts with that color. Basically a color grows until it fills up a 36 liter box, and then splits, but there are exceptions like “Dark Red” of which I have a 18 liter box for the miscellaneous bags, but also a 9 liter box full of “Dark Red Plate 1x2”, as I need them en masse for brickworks.
• Sometimes, I have boxes for groups like “Yellow Bricks”, “Yellow Plates”, “Yellow Tiles”, “Yellow Slopes”, “Yellow Technic Parts” (all depending on the amount) and “Yellow Other”.
• With other colors, depending on the amount, I may even split those in e.g. “Dark Bluish Gray Plates Small”, “Dark Bluish Gray Plates Medium”, and “Dark Bluish Gray Plates Large”.
• And, while I do have a “Dark Bluish Gray Plates Small”, the “Dark Bluish Gray Plates 2x4” have an extra box on their own due to the amount I’ve got.
• Some parts I have so many of that I have dedicated large boxes for a single kind of part of that color, e.g. “Black Slopes 45° 2x4” or even several large boxes like “Dark Green Leaf Elements 5x6”.
• Most of those “group” boxes are of the 18 or 36 liter variant.
• Most of the “dedicated” boxes are of the 9 liter variant, but 18 and even 36 are not uncommon. The parts are usually specially collected/bought for previous or for future projects. Like I have an 18 liter box of “Tan Plate 1x2 with one Stud (Jumper Plate)” from a past project.
• I have two shelves of boxes for black parts alone, one shelf for Dark Bluish Gray, one (currently overflowing) for Light Bluish Gray, one for Tan and Dark Tan, and one for Green, Dark Green, and Lime Green. All the other colors share another five shelves.
• Boxes may “grow” or “shrink” or even “dissolve”, depending on the project state. At the moment, I have only three smaller projects built as MOCs, and over 10 square meters of landscape and stuff torn down, so most of my parts are shelved. When I build larger MOCs for which I have collected special parts in large amounts, even a 36 liter box of single parts can vanish in no time. I had a box of “Light Bluish Gray Plates 16x16” before I started my Moonbase project. Now I’m down to exactly one plate, which moved into the “Light Bluish Gray Plates” box, together with the original boxes tags (I have laminated signs for my boxes). That box will soon be reactivated (I’m expecting another 100 plates in the next month or two), and then deplete over the building time of the project again.

Juggling that man parts is a headache alone. On top of that I’ve got a stack of ten boxes of “presorted” stuff, i.e. parts coming back from cleaning and drying which are already bagged together with new purchases which all have to move into the right storage boxes.

I hope that answers your question…