I'll be honest with you - they both can help quite a bit. BUT, I don't think they're enough if you need to be stealthy enough to have company in your house. The only way to do this is a carbon filter and a fan. There are some tutorials on how to make something like this yourself, but it's in your best interest to have a carbon filter in your room or attached to the box somehow.
I have a box about that size, and even one or two plants will make a very noticeable smell late in flower - enough that I don't think the odor control bucket or ONA gel would cover it on it's own. Frankly, I know they won't - at least not in my experience.
There are a lot of ways to reduce or mask the smell, but without a carbon filter an observant sniffer will smell a skunk late in flower. That's just my opinion, but it's an experienced one. The suggestions you got are excellent, as they are the best ways to do SOMETHING on a low budget, but some things are worth saving and waiting for if they, for example, keep you out of jail, if you know what I mean.
Sorry if it sounds like I'm being a buzz-kill, but I don't want you to do what so many do - get down the path of a grow and BAM - a skunk died in your house and you're not prepared. That's about how it happens, too. One morning you wake up and the whole house smells like a skunk. It might cost you $150 - $200 for a good fan/filter (tops I'd think), but how much is bail?
Second best thing is probably a ozone generator, in my opinion. There is a model called the Ozone Jr. for around $75 - $85 that you can google info on, and it would be a nice size for your setup. In your case with one plant, it might be enough to get you by, but I'm not as confident in that as the carbon filter and fan - (though they are pretty effective overall). If you can't afford either and are okay chancing it, w1sest's and jwb's suggestions are the best low budget. I do all of them currently except the odor bucket. Even then there are times where I'm dousing the house with air-fresheners, too!
Again, I sincerely want to help you out here and this advice is coming from a caring supportive place -