I have made a price list of products I purchase on a regular basis at Aldi. This helps me do price comparisons with other stores to see if the "sale price" is really a good deal. Please note that while most items on this list are at a fixed price, I have noticed that some of them do fluctuate: namely milk and eggs. Also, occasionally, Aldi will have a "price drop" (as we saw this week with the butter and crescent rolls), which is nice!
Anyway, hopefully this list can help you too - it's not exhaustive (only the stuff I buy, and I've already noticed I forgot some items), and it's bound to somewhat change, but at least it's something to start with! Have a great weekend!