The Short answer based off craftster guidelines
1 point is equal to any of the following 3 things
1 craftster small, 1 hour of crafting time or $10
so 2 points is a craftster medium, 2 hours of crafting time or $20
3 points is a craftster large, 3 hours of crafting time or $30
1 small 1 medium and 1 large would be equivalent to 6 points, or 3 smalls 2 mediums and 1 large would equal 10 points, which is our point range, if you crafted 10 smalls that would be 10 points, or 5 mediums would be 10 points, 3 larges and 1 small would be 10 points, etc...
I have seen different arguments on what the $ value means (some say it's the cost of materials, some say it's the final value of the finished piece)
My personal take on the number system vs set sizes (and this might be a wordy post lol) But I think it might be helpful to others in other ways too
I prefer points because my ideas don't come necessarily come to fit a particular size. And I don't like feeling like I should have to alter my ideas to fit a size guideline set by someone else lol, and I don't want (as an organizer) to limit anyone else's creativity in that same way.
Also I find many times my crafts could fall in all 3 categories, for a recent swap I made a floral scarf. The materials were not substansial (at very most like $5 total used material in the item, but much of it was scrap yarn so really it was free from other projects) The scarf was completely freeform, roughly 10 feet long and all worked on the piece, because of the way I did it, it took me about 6 hours to complete it.
Using this scarf as an example, based on $ value of materials it was a small, based on time invested it was an XXXL, based on craftster item size guidelines it was a medium (scarves fall there If I am remembering correctly) If I were to sell it the price basis would be in the Large to XL range ($30 to $40 or more). So it makes it really hard to determine where something falls all too frequently for me.
So I take the categories it could fall into and average them to determine what size the item is when finished. Then i consider the way I would feel if I received such a thing in the mail myself, would I feel like I had received a small or a medium or a large?
And after I determine a size, I also factor in my 'crafting ability' in different areas. In some areas I am an expert, and in other areas I am a novice. I try to consider how my experience might look to someone that is more experienced than me. I also try to consider that what took me X hours as a novice, someone else with more experience, may have been able to create the same item in 1/2 the time it took me. So I factor that in too.
In regards to the scarf, I did decide it was a large. But felt a little silly about that because it wasn't as substantial as other things I had done, and again I am a novice in that craft. (only seriously crocheting for a few months) I then compensated for my weaknesses in that craft with extras I knew my partner would enjoy.
On the receiving end, however, I consider 2 things in a swap "Did my partner make this item with me in mind?" and "was it made with love?" If the answer to those two questions is yes it's almost a guarantee that I will love whatever they have sent me. It's not about the money spent to buy the supplies for me, but it's about the thought and time someone put into creating something just for me. And that completely rocks.
Anyway that is just my 2 cents (and the reason the swaps I organize are on a point basis vs a set size basis, and in the case of this swap, it just leaves it open for even more random goodness!) I wouldn't typically post this so publicly, but I really am curious about how others feel about sizes, and what methods you may or may not use to determine what size you consider something to be when finished.