Adding a table with items and prices to a drupal site
Your question consists of 2 questions ... I'll use the same numbers to answer them.
1. Alternatives to using Custom Content types
a) Use Drupal Entities (Option 1)
Use the Entity Construction Kit (ECK) module to create 'entities' (= fieldable things ...) like Products and Prices. For each of those entities use &quot;fields&quot; for each of the columns you mentioned. Should you run into fields such as dates, you would have to add modules such as date also.
For the &quot;foreign keys&quot; use the Entity reference module (possibly some related modules of it also, extending its functionality, as mentioned on the ECK project page) and/or the References module (cfr. 'node_reference' and 'user_reference' as contained in CCK for D6).
Maybe modules like Display Suite or Panels could help to enhance the look and feel of it all also?
b) Use custom tables and/or an external database (Option 2)
Custom tables are tables you create yourself, in the same Drupal database. External Databases are databases that are different from the Drupal database, which are typically in formats such as Oracle, PostGress, MS Sql, MySQL, SQLite, some PDO compliant DBMS.
Using this alternative, you can use the Forena module for reporting about the data from within a Drupal site (as further explaining within &quot;reporting&quot; below also). To perform updates (delets, inserts, etc), you'd use your own tools that you'd prefer for the DBMS of your choice. Same for creating the tables, etc.
2. Reporting
Consider using modules such as (either one, or both, depending on your requirements):

Views, combined with Views Calc also probably. Have a look at How to calculate the sum for each option of all webform results in a Drupal webform grid? to get an idea of using Views Calc.

Maybe you want to consider the Forena module as a supplement / alternative. E.g. if you'd need to also create charts or so, or if you have a need to access data in some external database such as MS SQL, Oracle, etc. Here is a quote about it:

... built of the idea of using SQL to get data out of a database and use XHTML and CSS to format it into web reports.



Disclosure: I'm a (co-)maintainer of some of the modules mentioned,
I hope this does not violate the site's policy on self-promotion.