Nathan, it's a dilemma this one. I hate taking my mobile phone with me when fishing, but due to illness my wife runs me to the river, and I need to phone her when I want picking up.
So I have to take it, it has a reasonable lens for close up photos so would cover the odd big fish picture if it ever happens.

I always have it switched off on the water, as the last thing I want is a mobile ringing when I am fishing.
But I bought one of these waterproof camera bags off ebay for about £6, and it seems OK.
I wouldn't like to trust it for a severe immersion of any length of time, but on the odd occasion I have had a sit down in the river, which is more often than I care to admit, it has kept it safe.
It has three seals on it and seems to keep the water out quite well, better than nothing.
Have a browse on ebay they are still for sale I think.
Certain mountaineering / fishing shops sell them, but at a price!!