I made a site for a client with almost these exact requirements (minus the
SEO and batch upload). I took their requirements. snipped out everything in the top box and told them this would take 6 months to do properly and priced the work accordingly. For a US company I say $30k is cheap. Keep in mind decent programmers working for a firm make $40-60k a year conservatively. Top that with a 25% overhead costs for the firm and your only looking at being able to hire a single programmer for less then 6 months.
Again these are US standards for work. $1.5k is an EXTREMELY low price (I won't consider a larger project for less then $1.2k) and I would doubt their abilities.
This thought process has pervaded a few of my clients. Yes, a programmer can mash-up what free code he can find (license permitting) to give you a site. But then you have to deal with security issues related to the software your using (now you need to worry about upgrading 10 different packages). Additionally only the coder who wrote it will really be able to upgrade it because he will likely have hacked the core files and you won't know what he changed. This will end up costing you more money every time you need to push a new security patch or major version upgrade.
In the end the mash-up of code will cost you more money, and with the mash-up you won't succeed because it will quickly become a massive headache.
Sorry you get what you pay for and you want a LOT for not much apparently.
When considering the bids ask them how long you think it will take, press them on security issues, ask them if they stand by their code and if they will track and fix security issues for you (they should do it free, I have never had a problem with a paid project).