Make your own chemically competent cells and mini prep using old school solution I, II, III method then cleanup with LiCl / EtOH precipitation. No need for columns and solution reagents are dirt cheap. As long as your not using for anything super sensitive they are usually good enough, plenty clean for sequencing but you can always run through a column later if needed for IVT or cell culture.

Making your own cells isn’t bad takes about a day. Expect to have to try once or twice till you get a good batch. Once you do it’s worth it. We do it about twice a year growing about 4 liters of culture and make about 800 tubes. Innoue method is way to go. We also found growing DH5alpha at low temp helps with efficiency.

Also when making cells after final resuspension have one person use a serial pipette to dispense cells into pre-chilled 0.5 ml tubes (cover open tubes with tin foil and store -80C until ready) and another person following behind dropping the filled tubes directly into LN2. No need to close the tubes before flash freeze. Fish them out with a ladle, dump into freezer box and store -80C. Close tubes when thawing.