I don't know enough about share prices to answer your question, but the UCI Machine Learning Repository is an good resource for real data that you'll likely be able to use for any purpose, as long as you cite them.
From their website:
The UCI Machine Learning Repository is a collection of databases, domain theories, and data generators that are used by the machine learning community for the empirical analysis of machine learning algorithms. The archive was created as an ftp archive in 1987 by David Aha and fellow graduate students at UC Irvine. Since that time, it has been widely used by students, educators, and researchers all over the world as a primary source of machine learning data sets. As an indication of the impact of the archive, it has been cited over 1000 times, making it one of the top 100 most cited "papers" in all of computer science.
The citation policy:
If you publish material based on databases obtained from this repository, then, in your acknowledgements, please note the assistance you received by using this repository. This will help others to obtain the same data sets and replicate your experiments.
A few data sets have additional citation requests. These requests can be found on the bottom of each data set's web page.
If you filter by "business" there are few datasets which look like they might contain the right type of information. It might be worth the cost of citing them in order to use them (only necessary if making your public, I believe) because they are free to use for any purpose otherwise, as far as I can see.