I always suggest ratchet style OEM crimp tools. They are typically $300 to $500, but without them you are exposed to many issues in electrical connectors. Remember that electrical fires suck. Also there are procedures for inspecting your final crimp connection. For DIY folks who don't do this every day, I suggest finding the procedure and inspecting every connection. Typically that means after it has been crimped, you measure it with some calipers and verify that it has not been over or under squished. If it has been over or under squished, your ratchet style tool can typically be adjusted to increase or decrease the crimp forces. I suggest the ratchet style for this reason, it is very difficult for non-ratchet styles to get the proper crimp force.
In industrial land, the mate-n-lok is a very common low cost connector. It is typically used in dry conditions, and can be used in wet areas with additional components. The $/connection is much lower than the above mentioned connections, as well 1 crimp tool allows both lower cost dry connections as well as weather resistant connections. Here's a quick list of key features for this connector.
-- Gold plated or TIN plated contacts
-- There are options for PCB mount, harness mount. bulkhead mount, and strain relief shells.
-- Different shell sizes are available to make for easy to see keying, and to keeps costs low if you don't need extra connections.
-- If you have many connectors, you can get additional keying options by changing male and female pins, such that 2 shells that are the same can not be connected.
-- Contacts can handle 10AWG to 30AWG wires, 600V, and up to 19A.
-- Optional weather resistant seal's
-- Lots of engineering details including vibration, shock, wire pull forces, salt spray, contact resistance over time, amp ratings for different shell configurations, etc.
See pages 169 and 170 in the below datasheet about mate-n-lok connectors.
http://www.te.com/commerce/DocumentDelivery/DDEController?Action=srchrtrv&DocNm=82181_SOFT_SHELL_CATALOG&DocType=CS&DocLang=EN
See Product Specifications
http://www.te.com/commerce/DocumentDelivery/DDEController?Action=srchrtrv&DocNm=108-1031&DocType=SS&DocLang=JP
See Application Specification
http://www.te.com/commerce/DocumentDelivery/DDEController?Action=srchrtrv&DocNm=114-1010&DocType=SS
See Selection Charts
http://www.te.com/commerce/DocumentDelivery/DDEController?Action=showdoc&DocId=Specification+Or+Standard%7F408-7300%7FE%7Fpdf%7FEnglish%7FENG_SS_408-7300_E.pdf%7F640582-1
See crimp inspection (you can typically do this with normal calipers. However they show fancy micrometers)
http://www.te.com/commerce/DocumentDelivery/DDEController?Action=srchrtrv&DocNm=408-7424&DocType=SS