PAYG Huawei E3131 Tmobile Dongle £9.99 @ Currys averaging over twice that on Ebay (free or £2 unlock) - Impressive 21.6meg download and 5.76 upload.
£9.99 in store only, though can be booked online. Applies to PC World collections too.
3G/4G UMTS / HSPA + Frequency: 2100MHz/900MHz
2G Frequency: GSM / GPRS / EDGE 850/900/1800/1900 MHz
Data DL Speed: Max 21 Mbps
Upload Speed: Up to 5.76 Mbps
MicroSD memory card slot up to 32GB
Suppot Text messages,Broadcast reception and Group SMS
Antenna: Built in and support external antennas (probably crc-9)
Number of entries in the phonebook: up to 100
Supported Systems Windows XP,Vista Win7 or above
Weight: about 30g
Waranty: Full One Year
15p from Quido, but don't spend it all in one shop!