On the principle of a spare I would suggest holding out on planning to have a spare.
Unless you are competing and must have a gun ready then having a spare just in case can be counter productive.
If your main super fancy perfect gun does not work, then fix it. Take time out from a game to check the fault, learn about it, maintain it. If you can't work out what's wrong then you can ask for assistance. Other people might not want to take time out all of the time but we have a friendly community and people like to help each other and pass on knowledge
If you just put it down and pick up the spare reliable always functioning gun then you have not learned the lesson regarding the primary. You still have a gun to take home and fix. If you get home and don't know how to fix it then there is no one around to help - only the internet for people to have opinions on what may be wrong
Spares should be acquired over time when you can't justify letting it go, not bought as a spare
Sometimes I bring loads of guns and play with one, or play with a selection. I've even had times where i pick up a gun and have a problem, pick up a spare and have a problem, pick up the next one ....
Then take time out, have a think, pick up the first one and it's running in minutes
good answer Tom Ive brought a Excty for the reliable work horse (Im not made of money and new to the sport)
And have a Diadem as my toy (about 10yrs old)
At our last tournament my marker went down ! A great Guy from Outpost stripped it down for investigation then looked at me and said "have you been fiddling with the trigger?"
Lesson learnt !
My advice to you clappy is get a decent mask a marker that fires and get out there Tom is right its a friendly sport and just a couple of tournaments and your be full of knowledge.