It varies from store-to-store. With downloads, you will be paid the wholesale price attached to your track by the particular store. Stores generally take about 20-30% of the retail price after sales tax.
With streaming, when a subscriber to a store streams your music you get paid a proportionate share of the subscription revenue (or, if the service is ad funded like Spotify’s free tier, the ad-revenue) collected by the store in that particular month. This means that payments will vary from month-to-month depending on the amount of subscription or ad revenue that was generated by the store and how often your music was streamed.