You get what you pay for
It's possible to get a family camping tent that's very inexpensive. But even if you'll be taking the family camping only once a year, it's wise to consider quality. You don't want to be miserable.
- Poles should be easy to attach to the tent; they should fold down so they're easy to transport. Most segmented poles are connected by shock cords so you won't lose any of your belongings in inclement weather. Strength is important. Metal-tipped fiberglass poles may be cheaper, but aluminum is sturdier and won't rust.
- Backpacking tents are usually made of nylon because it's light, but polyester, which protects against ultraviolet rays better, works well for family tents. Check seams to make sure they overlap well or are taped and sturdily stitched. For summer camping, look for plenty of mesh panels for cross ventilation. Denser fabrics are better in extreme weather. Rainflys and tents may be waterproofed with silicon or polyurethane.
- The zippered doors of family tents will get a lot of use, not always careful use. Make sure the zippers work easily and are durable.
- The tent's floor should be one piece and a "tub" or "bathtub" style, so the seams that join it to the sides are several inches above ground level. Otherwise, moisture may pool and seep inside.
- Many tents are freestanding -- they are raised and supported by their external poles without the need for stakes. Even these should be staked at the corners and sides, or they can blow away. Look for strong loops of nylon webbing and stakes of titanium or aluminum. There are special stakes for sand. High-quality tents will also have guyout loops so you can attach guy lines in rough weather.