Best way to anchor a pipe in the ground

Would a a U-Post or T-Post be okay for your purposes? Drive it into the ground with a sledge hammer or post driver and spray paint the above ground post to whatever color is desirable. It has holes and notches that could be used to attach the lights. These posts are normally used for fencing and without pouring concrete. However, consider if they are safety hazards for your particular installation and how to mitigate that or don't use them.

Here's the link on Home Depot for U-Posts. I ordered a bunch of these online for garden fencing and Home Depot shipped them to my house for free.

Home Depot also carries safety caps for T-Posts/U-Posts and a metal post driver which is much easier & safer to install posts compared to a sledge hammer.

U-Posts are lighter duty than T-Posts but would be plenty sturdy for holding lights. If T-Posts would be your preference, you can get them at places like Tractor Supply.

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or set the posts in quikcrete in a 5 gallon bucket

I did this a couple of years ago. I used a 2x2 square pipe and put it in the ground about 2 to 3 feet and poured 2 bags of cement around it. For the lights, I went with a ss cable and two tensioners at each end, with a pulley on the pipe because my distance was so long. just ty raped to the cable. 4 years later never drop. here is a pic

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