Speakout seems to use Nokia phones. Nokia makes great durable low-cost phones and it's easier for a small company like Speakout to just deal with one company.

Unfortunately Nokia has only recently come out with a consumer (ie Low-cost) device with a full keyboard (all their previous qwerty phones were high-end business devices) called the Nokia Surge. AT&T has just started selling it in the US for $80 US WITH a 2year contract and a minimum $30/mth data plan - meaning AT&T subsidizes the phone and the real cost is a lot higher. So, I'm not sure if the Nokia Surge is low-end enough for Speakout to sell it. Perhaps Nokia will come out with a low-end Surge and Speakout can sell that. But that's a while away - just check out Ebay and get whichever phone you like.

I can recommend the phone I'm using with Speakout - the HTC s620 (aka HTC s621, T-Mobile Dash). It cost be around $130 on Ebay back in January, might be less now since they have come out with an upgraded model. It has a Qwerty keyboard like a Blackberry, runs Windows Mobile (some people have upgraded it to Windows Mobile 6.1), and has WiFi <-- which is important since that's the only way you'll be able to browse the web with the phone and a Speakout sim. The Samsung Blackjack and Motorola Q9 are similar, but both do not have WiFi (or at least most of them don't) since they rely on the cellular data network for internet access.