Cheap power tools for large number of cuts of aluminium profile lengths
Any circular saw will cut aluminum, copper, or any other non-ferrous metal easily with a sharp carbide-tipped blade.

Keeping the cuts straight, square, millimeter accurate and not damaging thinwall parts will require some guides. My preference would be a radial arm saw, the length is easily handled with a clamp on the fence. If you don't have one, buy or rent a cutoff saw and build a jig. Time spent building it right is repaid tenfold when you cut all those pieces.

Use a new blade - the one that made your deck 5 years ago will make a mess of the aluminum. And get some earplugs too - cutting metal tubing makes noise roughly comparable to the Space Shuttle lifting off.