fix: initialize totalCost correctly and refactor blessing purchase logic

[omarcopires]

Description

This PR fixes the initialization of the totalCost variable and refactors the blessing purchase logic. Improvements include replacing string concatenation with string.format for more efficient formatting, as well as adjustments for better code clarity and readability. The code is now more organized, and the calculation error has been fixed.

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)

Checklist

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I checked the PR checks reports
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud