I haven't ever used e-mail for bids, just seems a tad informal.
Registered post (proof of delivery) with a stamped and signed quotation is standard here.
This way there can be no excuses:
- of your bid not being received or somehow lost
- not delivered on-time (tender dead-lines)
- being incomplete, informal or invalid as a legal document (debate on electronic signatures)
- or altered/modified in retrospect
In any case, you're spared of the legal runarounds some site's like to use.
F-250 5.4 V8 stand. cab, tandem trailer
Ferris IS3100Z 61" L Kaw, Hydrocut 36" 13hp Kaw
Shindaiwa T3410, EB8520 Maruyama HT2300, MS047
Stihl FC85, MS192T, 041AV, MS200