Tell and show a lot more about it. Why are you concerned aboutv authenticity? Pix? A serial number tells hardly anything.

Yeah...just as to its value but I'll buy it anyway so I can take it on camp trips

Are there any indications of who made the banjo? Some name on the headstock? We need pictures: headstock, front and back of banjo, fretboard, any identification marks.

This is an authentic banjo.  

pictures below from BanjoWannabee's media file:

Post-1975; cheap; Asian.

Post 1975, inexpensive serviceable student model made in Asia. If there are no structural problems and has a proper set up. (1/8" action at the twelfth fret with a bridge that is 1/2" tall or higher), then it can be a good student banjo. Market value is $100-$200 in the USA.

Authenticity is not an issue. Same banjo with no name or many dozens of different names. Right now, if I ordered one hundred of these from China, they would be happy to put my name on the headstock.

Lots of those type come through the shopgoodwill website. Can be had for $20ish to $100 tops depending on the condition and quality of photos. You DO need to have some banjo set up knowledge for most of them. I’ve fixed up a number of them, and they make decent beginner banjos. The one in the photo looks like it may have a truss rod, so a plus there. The photos are blurry, but the 5th string tuner looks wonky, maybe bend or busted.

wannabee, "authenticity" really isn't the issue with the banjo in your photos. SERVICEABILITY is the issue.

Several have already explained this is a base/beginner's model resonator banjo made in Asia since 1975 or so. They are all of a piece. Just about as cheap a design and execution as can be found.

The rest depends on YOU. What kind of music are you hopeful of learning? Bluegrass? This is rank beginner's banjo for bluegrass --- because it has a resonator. If you're more interested in old time fiddle/banjo music, the resonator is more or less unnecessary. It does no harm unless the seller uses it to raise the price. The majority of old time music beginners use an open back banjo.

As for serviceability, you have to have it "in hand" to begin to evaluate that. Is the neck tight and securely fastened to the pot? No wiggling looseness! Sometimes looseness can be easily tightened up; sometimes not! It might be well built, but poorly assembled, you see. Is the neck straight and not bent/twisted/bowed? Sight down the length of the fingerboard on both edges and hope to god it's straight and level. Do all 5 tuners work well -- not stuck, jammed or rough to turn? Is the bridge tall enough that none of the strings drag on the frets when you tune it up? It's best if you can get this banjo in your hands, to tune it up and then try every string on every fret to be sure you get a clear note, not a "splat!" The head should be tight and flat (the feet of the bridge should not VISIBLY press the head down the thickness of a dime or more.

Then it boils down to price. As you saw from others, this type banjo sells USED for up to $200. You shouldn't pay more! (Unless maybe it includes a nice hard shell case.) This is THE most common used banjo you'll find. If something is wonky about this one, just wait and a dozen more will show up for sale soon, especially if you shop on line.

In other words, don't buy it without inspecting and strumming it IN PERSON first. And then, don't overpay. You can buy a LOT BETTER used banjo for $500. Oh yeah, when you inspect it and play it, you must LIKE IT. Don't buy any banjo that doesn't make you feel happy.

After viewing the better resolution photos on the OP’s page, the 5th string tuner looks ok. The headstock says Fender on it, and a Google image search shows it as a Fender FB300 which was discontinued in 2014. It was valued at $199 - $250 and came as a value pack with gig bag and accessories.