I've dumped a load of money into buying secondhand on these forums lately, and as I stated I've only really been stung on the mask. I had an issue with my marker too but it was nothing that affected performance so I doubt the previous owner even noticed it. I was nervous about buying on the forums too at first, but found it to actually be pretty safe. You only really have to look at the strength of the community's reaction to fraudsters. That being said, I still think you're right to feel guarded about it. After all, the only thing someone needs to become a forum member is an email address. So here's a few assorted ideas I picked up whilst hunting for kit that may or may not be of any use to you at all!
Another awesome offer I just discovered you might care to take advantage of. Empire E-Vents were mentioned as a good mask choice; Vents Avatars are the same sort of design but with less venting (ironically) and no soft ears. I picked myself up a pair of these and think they're pretty great. The reason I mention them is because they're on offer over at Just Paintball for £40, which is good off the bat, but then I noticed they're also auctioning them on eBay where I've seen them go for as little as £25 delivered. Considering you won't get the lens on them cheaper than £14, that's a pretty freaking excellent deal in my mind. However, it's worth splashing out on your mask because faces are pretty important so your original idea of just getting the Dye i4s is still potentially the better one.
- At least for the marker try to buy from trusted forum members; whilst the issue with my marker didn't cost me any money it has been pain to fix. When I say trusted, I don't necessarily just mean "known to send people the stuff when they pay". It's also worth looking into who they are from their forum posts. Do they sound like a techhead? Then the marker's probably been looked after. As I previously stated it might also be a good idea to see if they bought it off these forums before, because then you know if it's second hand or billionth hand. Plus if they're selling it shortly after they bought it, maybe it's worth questioning why.
- If you're buying something from someone with zero post count who seems to have just registered on the forums to post the sale thread, don't be afraid to get some details from the guy first. I asked for a home address and landline number that I could call to check they were in fact a real and actual human being. Also there's something screwy with post counts that I don't quite get; I bought my marker off someone with next to zero post count, but his post history showed significantly more posts. Maybe some forum change reset the counters at some point? No idea. Either way, might be worth checking.
- When you pay using Paypal payment-owed you forfeit your ability to open a Paypal dispute for an undelivered/broken item. It seems to be accepted practice on these forums that the buyer pays an additional 4% on top of the final cost to cover Paypal fees if you want to pay in a way that gives you buyer protection. I find it odd that people are okay with this, but I get that there's a lot of trust in these forums. Regardless, if I were you I would always pay the extra.
- Try to get to a local walk-on to look at some kit before you buy. I mean actually do this. I think people give this advice because it sounds like a smart thing to do but they don't realise it's a pretty weird thing to show up at a place like that with no kit (or even necessarily an intention to play) and be all "oh hi, bunch of strangers, mind if I handle your belongings?". It's not so bad when you already have your own stuff because you're there playing with them. So I know it sounds weird because it did to me too; best way to handle it is to find the walk-on through these forums or asking around, and e-mail whoever's in charge. Just see if they're cool with you doing it and let them know when you're coming; it'll take the edge off. I did this and found that just about everyone there was more than willing to pile me with advice, and one guy even let me fire his Invert Mini (which in turn led to me buying mine ). In fact, you might even be able to join in the walk-on with some site gear as one kid present was doing. Oh, also someone might be selling something there, and testing a marker before you buy it is the best you can hope for really.
Another awesome offer I just discovered you might care to take advantage of. Empire E-Vents were mentioned as a good mask choice; Vents Avatars are the same sort of design but with less venting (ironically) and no soft ears. I picked myself up a pair of these and think they're pretty great. The reason I mention them is because they're on offer over at Just Paintball for £40, which is good off the bat, but then I noticed they're also auctioning them on eBay where I've seen them go for as little as £25 delivered. Considering you won't get the lens on them cheaper than £14, that's a pretty freaking excellent deal in my mind. However, it's worth splashing out on your mask because faces are pretty important so your original idea of just getting the Dye i4s is still potentially the better one.