Choose your first miner by its job, not its jackpot
Separate a learning project from an income calculation before comparing hardware.
Decide what success looks like
A first miner can be a learning project, a hobby or equipment you expect to earn money. Write down which of those you want. If your goal is learning, successful setup and an understanding of the dashboard are useful outcomes even without a payout. If your goal is income, the purchase needs a cost model. A screenshot of somebody else's block win answers neither question.
Understand the work
Bitcoin mining competes to add valid blocks to the network. Bitcoin.org describes this as a competitive lottery governed by network rules. More hashing attempts improve a miner's share of the opportunity; they do not make a small device's next reward predictable. This is why it is useful to distinguish a tiny learning device from an ASIC designed to perform much more hashing work.
Compare the complete setup
Before comparing two listings, put the miner, required power supply, cooling, shipping and any necessary setup parts on the same sheet. Read the exact model's documentation rather than assuming a connector or supply fits because the photograph looks similar. Ask what is included, who supports the device, and how you would recover after a failed update. Cheap hardware can still be an expensive first lesson if essential parts are missing.
Pick a stopping point
Set a total hobby budget before shopping. For an income experiment, decide in advance how you will record electricity use and payouts and when you will review the result. Keep a separate line for the original purchase. Recovering daily electricity expense is not the same as recovering hardware cost. The right first device is one whose limitations you understand before the box arrives.