Kits are a great way to get started in hobbyist rocketry. Rather than picking out all the components yourself, you can buy a kit that comes with most of the hardware you need to build a rocket. The resources listed below are all retailers that have kits geared towards rocketeers attempting their L1 certs.
Wildman is a vendor focused on fiberglass rockets which are much more robust and resilient than cardboard or phenolic rockets. This kit is small at only 3in in diameter but will be able to fly for many flights in the future and it’ll be much more likely to survive a hard landing or early chute deployment. There is a build video tutorial and rocksim file available for this kit which can really help in achieving a successful cert. They also sell other vendor’s kits like LOC but I would recommend checking out LOC’s site unless there is a really good deal on Wildman’s
LOC has been making rocket kits and components for a while. One of the most popular cert rockets is the LOC-IV. This kit is a cardboard kit but is a little bigger than the fiber glass kit and comes with a parachute. Like the Journey 75, there is a video tutorial on how to build it. This kit is a little less resilient than a fiberglass kit but is also lighter and cheaper. I have flown a kit similar to this up to an L2 but after about 3 flights, the rocket is pretty beat up and would need some repairs before flying again. This type of kit would also not survive any launch anomalies like an early chute deployment or hard landing from a tangled parachute.