I'd prefer a fixed-price contract based on milestone payments, for example $40 for about 8 hours, or $60 for about 12 hours.
Relevant Skills and Experience
Since 2013 I've been doing manual testing (more SDLC models, agile frameworks, scrum; UI/UX, functional, usability, database and regression testing of database-driven web and desktop applications).
Proposed Milestones
$40 USD - initial exploratory test round: 8 hours in 2 days
$210 USD - each milestone based on a commonly agreed to-do and amount
Additional Services Offered
$1 USD - using / administering an online bug tracking system
My desktop system is running Windows 10 Home; I can use current versions of Egde, FireFox, Chrome.