Unfortunately they don't post prices on their website . . .
One thing you and I both agree on is companies that don't post prices are a hassle
Yep, it's a dead giveaway that the prices are (too) high and Linak are
pretty expensive (but also pretty good), just like I've heard about Firgelli, but I don't have personal experience with the latter - buy local, the politicians always say
Another reason for not having prices on a site may be regional pricing. I bet you can buy a Linak cheaper than me, even if they're a Danish product - same thing with LEGO, which costs more than twice the US price here in DK... Buy local, ha, not as long as Danish products are cheaper in every country in the world besides Denmark and considering that their inland market is only a few percent of their totals, I think it's an embarrassing utilization of very strict import duties, against the very country that supported them when they were "growing up"
For cheap linear actuators, I've used 10mm threaded rods in a length of water pipe with a nut welded to one end. A Nylon tube in the remainder of the pipe can be used for longer travels, but for the ~3" I needed, I went with just the nut (runs in guides anyway).
It's worth going for stainless rods (and nuts), as the threads are usually of a better/smoother quality than on the cheaper plain steel rods.
I've made nice dead bolts among other stuff this way and it is easily scaled down to smaller thread diameters - no need for weak glue stix, although they do have more travel per revolution (Imperial threads do have a larger rise than metric threads as well).