What Sandgrounder said above sounds pretty good, but really it's so expensive buying the jars (and to be honest, most of the baby food you will buy will be a lot older than your baby

)
Please forgive me if you already know this, but you can make a big batch of single puréed food, and freeze into icecube trays... (once frozen you can put them in freezer bags) they will last for weeks... If you're going out for the day, or even over night, you can take food straight from the freezer... It will defrost on the way....
I guess the plus with baby jars is that if you don't use it, it's not lost, but if you don't use the food you make, it's not a big deal... it probably would have cost you 1/50 of the price to make...
Buy yourself a supply of containers I can recommend some plastic tupperware style ones around 250ml, that way they will last until your baby is much older.