I'm not sure if it's a terribly good business plan to start a forum that requires you to pay money to get visitors. Even with no expenses, forums don't really make all that much when it comes down to it. That being said, if I had a forum marketing budget, I'd probably spend it in AdWords and just pay per click-through.
If it's about active users, then I suppose you could pay people to post with those paid posting services. {shrug}
blog comments and forum comments for backlinks is what i'm doing doing it manually though not spending much money on it takes a lot of time
Forums don't need marketing as much as content for search engines to gain natural traffic. Forums can be incredibly rich in content for search engines and many top results are forums. Natural search engine traffic can account for 70% of your daily traffic if you rank well. Your goal should be to rank well. Do that and everything else will fall into place. So start with quality content even if you have to pay posters. Then work on SEO.
I would buy a nice HD digital camera - probably in the $600 - $800 price range, a lapel mic, get some easy to use video editing software that supports HD. Then start posting some HD videos on youtube. Right now I am posting regular (non-HD) videos. I have a wide screen camera, but it does not do HD. Just so you will know, youtube is my forums #1 source of targeted traffic. Over the past 2 1/2 years I have posted over 320 of my own homemade videos. This provides my forum with a steady stream of free targeted traffic.
I know Kev is big into his Youtube method and it's probably a winner but I don't think you need an expensive camera. You can probably get away with a Flip Mino HD. http://www.amazon.com/Flip-MinoHD-Camcorder-Minutes-Black/dp/B001HSOFI2
I could probably use something like that, but I am starting to do interviews with professionals in certain fields. And it just looks a whole lot better if you bring in a tri-pod and a nice looking camera. I would like a nice Sony that I could put a boom or shotgun mic on, or even a remote lapel mic with a radio transmitter. The one I'am looking at is about $2,500 brand new. Way out of my price range right now. The camera I use right now for interviews sells for about $300.
If you're doing interviews and good quality stuff sure you can splurge on better equipment but I don't see a reason to overspend starting off. Easy to buy cheap Flip and if it goes well upgrade when required. It would suck to spend $600 and then find out it's not for you or that your site isn't taking off by the videos. Sort of the same logic I use to start forums with free forums software like MyBB.
When starting off, no - do not splurge. The worst thing you can do is go into debt. When I first started posting youtube videos, I used the point and shoot digital camera that my wife and I owned. The resolution was pretty bad. Then we upgraded to a new point and shoot, and I finally learned how to improve the video quality with the editing software. Currently I use 3 cameras to film with, depending on what I'am doing: Canon SD750 - films at 640X480 and 30 frames a second. This is just regular point and shoot digital camera. Canon D10 water proof camera. If I go out to the woods, this is the camera I bring. Its drop resistant to 4 feet, water proof to 30 feet down,,,, so I do not have to worry about dropping it while on a hiking or camping trip. JVC MS120RU - just your basic digital camcorder. This camera holds 2 memory cards. When one gets full it switches to the other card. All of those cameras are in the $300 price range. I'am hoping somewhere around July, 2010 to get a much nicer camera that films widescreen HD and at least 60 frames a second.
I do a few promotional contests every few months to keep users active. I really don't have the time and money to do much else... Not looking to make a retirement off my forum. It started as a personal knowledge base for my friends and I but now we have some active members.
marketing mainly for me. i guess new forums cant afford not doing marketing. paid or unpaid marketing, thats the lifeline of a new forum.