Look into any Argos or Xtravision shop window and you'll see digital cameras starting from as little as €40.For €100, you can now get what would have been considered a mid-to-high-end camera as recently as three years ago: the prices have come down THAT much.
Here are the best models you can get on the Irish market at this price level.

Pentax Optio M85Pentax has made a big comeback in the past year, mainly due to its 'retro chic' models. But this entry-level device is probably the best camera you can currently get for around e100. With 12 megapixels, the camera has a three inch screen and a 3x zoom. Its big advantage over its rivals, though, is the inclusion of HD video recording, rare for a camera at this price point. It also has a rechargeable lithium battery, instead of having to rely on disposable AA batteries.
Price: €100 (including delivery) from Pixmania.ie

Nikon Coolpix L22In a bid not to be left out of the budget market, Nikon has come in with a strong line-up of entry-level models with pretty advanced features for the price-bracket. The 12 megapixel L22 has a three-inch screen and an excellent 1cm macro-focus lens. Its video shooting mode is quite decent, too. It takes SD memory cards and AA batteries.
Price: €100 in shops nationwide

Samsung ES15Samsung is a bit of a 'me too' camera maker, assembling components together rather than specialising in any one element of the camera-making process. The 10 megapixel ES15 is a run-of-the-mill entry-level compact model, with nothing that makes it stand out from its main rivals. It has a 2.5 inch viewing screen and a basic video mode. It's a little plasticky, too, compared to its rivals.
Price: €90

Kodak Easyshare C180Boasting the ability to shoot videos in HD (720p) mode, Kodak's C180 is a step ahead of most of its rivals. What detracts a little from the 10 megapixel camera is its slightly smaller than normal screen (2.4 inches). It is also powered by disposable AA batteries. The HD vide gives it an edge, but it's shame about the screen.
Price: €95 (including delivery) from Expansys.ie

Fuji Finepix A180This camera is as basic as they come, if you can regard anything with 10 megapixels as basic. It has a 2.7 inch screen and a 3x optical zoom. Thankfully, Fuji switched over from its niche (and pricey) XD memory card format some time ago. So you'll be safe using the SD cards you already have.
Price: €78 from Argos

Canon Powershot A480Canon's sub-e100 camera is a basic affair, though it does have an unusually design feature for an entry-level snapper: a metallic case. Aside from this, it's the usual 10 megapixels, AA battery power and 3x zoom. The screen is a little on the small side, at 2.5 inches. Canon camera being, generally, of a pretty high standard, this model is compatible with most computers, without installing any software.
Price: €84 from Argos
The main sacrifice made with compact cameras for under €100 is that they are mostly powered by disposable batteries instead of a single rechargeable one. They also are unlikely to shoot decent video and will be limited to a normal USB-out connection.
They will also have limited optical zooms (normally no higher than 3X), smaller screen viewers and no advanced software features, such as panoramic focus or 'smile-detection'.