QuiltingNinaSue and Onebyone are correct. As an ex-Walmart employee I can tell you that when you apply, you cannot specify in which area you are willing to work and you would have to give open availability. You would not be considered if you refuse to work evenings, week-ends or (in some cases) holidays. The front end--cashiers--have the highest turnover of staff. If you were lucky enough to get a floor (department) position, being the lowest on the totem pole would definitely mean the less sought after shifts. Part time is 12-27 hours per week. The few months before Christmas are the busiest. Jan-March see hours cut to the bone. The manager of the store makes a huge difference. I worked under two--the first was fairly easy-goingaltho he showed a lot of favouritism. The second was a nightmare.
If you really think you want to try it out, see if your local store is hiring seasonal staff for Thanksgiving/Christmas. At least it would give you a taste of the job.