So, these pegs are 6.5g each, but I
previously weighed Ti and Aluminium pegs, and found that whilst the Ti pegs I purchased weighed slightly more than these Alpkit ones, the saving is still only going to be marginal (for twenty tent pegs, you would save just over 43g in total!)
The only way you got a significant weight saving, was to use the North Face Ultralightweight Titanium tent pegs, which are so incredibly light (at just over 1g each) that even the North Face instructions say that they should only be used in very light wind conditions! I've never tried to use them for camping, since they seem likely to bend the first time I meet some firm earth, let alone a rock.

At £7-50 for ten, they're only 75p each, which seems relatively cheap for Ti tent pegs (previously I paid £2 each), so probably worth a go, if they're in stock, and you need some more pegs.