Hello
I did all the purées myself the first couple of months and then slowly introduced 1 pot a week each of fruits and veggie to ensure baby was used to it and not be an issue when travelling.
For the ones I did myself I just did a couple of kg of veggies at weekends and froze them. The fruits I cooked for 4 weeks, then just mixed them up raw so I did them fresh.
The pots: I used Hipp and Nestlé as I wanted brands I could easily find everywhere. You must look at the etiquette and decide which pots to get. Some Nestlé have strange stuff addedd but so do some others... so I would just read and get the ones with as few ingredients as possible.
Milupa now has a new range sold at Migros which looks real good to me and Nestlé has the Naturnes line which is meant to be the closest to a home cooked meal

Have not tried them though as my baby is not having pots any longer
One trick is also that as they get older, rather than buying the premixed pots with veggies and chicken, for example, buy the carrots and potato pot and mix it with the chicken pot. It will have less strange ingredients.
And bottom line, baby pots are heavily regulated in terms of what ingredients etc go into them so do not worry about it too much and go with what baby eats!
Ciao
K