What are the benefits of back-linking

Hello,
The company I work for has employed a SEO company who have been trying to maximise our site's searchability. Recently they have informed us that the amount of back-links to our site is very low (which is true) and they want to sell us a service to improve this.
I'm not a search-engine boff and I need to know what benefits there could be from paying the SEO company to find us relevant sites (free and paid) that will link back to us.
The main reservation I have about the service is that it costs £500 p/m. This seems costly to me and I don't know how much we will benefit from it. The company tells me it will be a 6 month campaign, so it will end up costing us £3k.
Of course the salesman tells me it's a great worthwhile investment, but I thought I'd turn to my fellow devs for some practical advice

Cheers!

You might as well light up a cigarette with that money!

Getting a billion untargetting low value links isn't going to do squat for your rankings. What you need is targeted on-topic links from authority sites.

I would recommend you start by reading the following:

http://www.google.com/webmasters/guidelines.html

Thanks for the reply,

I've read the Google guidelines before, I'm pretty sure the sites these guys pick will be of good quality and relevant to our company. The SEO guys we work with are actually pretty good and have been very honest thus far, but 3k sounds like a lot to get relevant backlinks to our site.
Does anyone know any good questions I can ask them pertaining to the value of this service? Has anyone else paid for this type of service before? Any good or bad experiences?

Cheers

it looks little too expensive. backlinks from high PR sites would boost yr sites PR.you can ask them that from how many sites u gonna get backlinks and PR of those sites.

check this site http://www.textlinkbrokers.com/ and check "text links by page rank" part u will get an idea of prices.search google for similar web sites and check what they say and their prices.

but still its too expensive to me

Thanks Puffin,

I checked their prices and a few others... £500 a month is beginning to sound like a standard price for getting backlinks from sites with high PR, no?
I agree, I must find out how many sites we will be linked to a month. The spiel these companies are giving makes me think this will be a good idea, but I'm still very wary.

Thanks for the help