What are you plugging into to record? Does it have phantom power?
A LDC (large diameter condenser) mic will give you the most 'bang for the buck' and can be used for both vocal and guitar.
Assume you are in the UK, I looked at the Thomann website.
AT2020:
https://www.thomann.de/gb/audio_technica_at2020.htm
XE 1XS:
https://www.thomann.de/gb/se_electronics_x1s.htm
A little more than your budget:
AT2035:
https://www.thomann.de/gb/audio_technica_at2035.htm
AKG P420:
https://www.thomann.de/gb/akg_p420.htm