Thank your new customer for ordering your album and for any impact their purchase might have on your career.
Explain that you have a special offer for customers and drive home any scarcity or time sensitivity. The most successful upsell offers present a “better, faster, cooler, or complimentary” version of what they just purchased. For example, if they bought 10 songs for $10, then 50 songs for $29.95 is hard to pass up.