Why haven SSD Prices risen so much recently?

Why have the prices of SSD drives increased so much in the past few months? I bought a 120Gig SSD for £64 just before Christmas and I wanted to buy another one now and when I looked around the prices were around £88 for the same type of drive, even on eBay the prices were significantly higher.
I don't know of any economic reason for this.
 
Don't really see that here. Just looked at 128 gig drives and they seem flat (except the popular M4 w/transfer kit up abot $10). Then looked at 256 gig drives - the M4's, 840 Pro and Plextox M5Pro have been flat for the last couple of months.

In answer to question:
.. Somtimes venders will jack up price when the demand increases (law of supply and demand)
.. Could it be that they have incresed the tax that the vender pays and are simply passing this tax incease on. We as consummers only see the "tax" when it is listed as a tax we pay - unfortunatly there are hidden taxes that the venders pay that we do not see.
 
USAFRet - Was that a sale price or normal price.
Reason I ask is that three -> five Monthes ago I bought both a 256 gig M4 and a 256 gig 830 both for $170 ON sale. Their normal price was Approx $200 -> $210 at that time. Looking to day the M4 is still normally priced @ $199. Bought the Samsung 256 gig SSD for around $200 on sale and it is the same price (not on sale) as it was then $240
Ref: http://www.newegg.com/Internal-SSD/SubCategory/ID-636

Will say that the "Spot" price of NAND does sea-saw (sinewave effect), so yes the prices can fluxcuate 10 % and tends to be seasonal. Then again as I indicated, Demand/availability also plays an important part, and demand for SSDs is constantly rising - Face it Stores will try to maximize profit and take advantage of increased demand.

For pjmelect, there is also the possibility that that Hidden taxes have increased in the UK, and The EU in general. Both here and "over-the-pond" Government’s are trying to increase tax revue.
 
^ If you are looking at $119 for HyperX, that is not a "Sale" price. The crossed out $130 is the "suggested Manuf price" and the $119 is Newegg's normal price - Normally the $130 is only at brick&Morter stores.
http://www.newegg.com/Product/Product.aspx?Item=N82E16820239045

What I am seeing @ newegg is LESS more aggresive sale prices on the more popular M4 (ie 3 day sale for 256 Gig M4 @ $170 and the Samsung 840 Pro @ $200)