Part-time jobs that fit around childcare - what worked for you?

I am looking for part-time work that fits around school hours and found a few evening shifts near Denver. I have read a lot of threads here and could not find my exact situation. Shifts are four to six hours and the pay is weekly. How many hours do they guarantee?

I worked evenings at a hotel. The hours were steady and the team was friendly, but weekends were busy.