Comment Re:Unrealistic budget (Score 2) 372
Which is fine if you want each half-wall to be a slightly different tint of blue.
Then you "box" the paint. Pick up sufficient paint to do the whole job, and if they are in several smaller tins you simply mix them all together in one big pail. Return to the smaller tins for convenience (certainly at least one tin, for later touch-ups).
Even when buying new, if you are obtaining several tins of the supposedly-same shade you should still box them.