It really is easier to rent than to buy. Interest rates are at an all-time high. Even if you have a credit score of 800 you're going to get hit with an interest rate above 8%. There is no avoiding it. When you buy the trailer there will be maintenance costs, payments, tires, propane, tire chalks, hoses, cleaning supplies, and all the incidentals you will need to buy to make the trailer comfortable for you and your family. You will probably have a payment over $400-$500 a month (around $5,500 per year, not counting all the other items we listed above,) and the gas mileage is going to definitely drop like a rock the minute you hook the trailer to your tow vehicle.
On the other hand, when you rent an RV or trailer you get the benefits of having one when you need it and everything except the cooking is pretty much done for you. The trailer is delivered and set up for you and everything is fine. All you have to do is have a good time. Something to think about.