It comes in two sizes: one sized for a personal item, and one for a carry-on.
Promising reviews: “BUY NOW! BEST TRAVEL BAG! BEIS [swap]! This bag is great! Literally don’t hesitate to buy it!! I have traveled on Frontier, Spirit, and JetBlue, all with no problem fitting inside the bag measuring size perfectly! BEST PART I traveled a lot this summer, to Mexico, Nicaragua, and Jamaica, all for 5–6 days, and all my stuff fit in perfectly!! I had three JEANS, two SHORTS, seven TOPS, five bathing suits, two sandals, one pair of flip-flops, and three makeup bags, plus a charger in the side pockets! If you want to travel on a budget, this bag is your best friend. Plus, the bag is super sturdy and made of great material with strong zippers.” —Franyeska Pravia
“So much room for packing with this little weekender bag. The shoe compartment is great for packing towels and shoes if you want. It fits perfectly under the airplane seat. All these little compartments to have your phone, keys, headphones, and wallet are very convenient. So many different colors to choose from, which is also nice. I’ve convinced my mom to get one and all my friends because it is a [swap] for the Beis weekender but less than half the cost.” —Hfr123
Get it from Amazon for $25.98+ (available in two sizes and 17 colors).