So this is more geared towards people who are new to flipping or just new to the members world in general and want to flip with a small cashstakc (1-3m that's my opinion on a small cash stack) so there are alot of "safe" flips u can each day to make little extra cash here and there while ur doing stuff like fletching or high alching or whatever ur doing at the GE at the time.
Now do understand this isn't a guide on how to flip this is more of a guide on what to flip i'm going into the assumption that you have and understanding of flipping if u don't check out OldSchoolFlipping's guide he has alot of great guides on flipping. Without further a do lets get on with what to flip.
Runes:
Runes are by far the best thing to flip on a low cash stack, if ur starting with around 1-3m ur not gonna be able to get as many but i do recommend staying away from the elemental runes (fire, water, air, earth) as they tend to be botted in f2p worlds so the margins aren't real instead i recommend u flip blood, death, and chaos rune. There by far the best runes to flip as there always in demand by all players. Now for the more risker runes (only reason i say this is they tend to fluctuate alot) is law runes as they tend to be in high demand a lot for players who are either skilling there magic or trying to get wine of zammys. Nature runes don't usually have margins change and there usually only a 1 gp margin but u can check them from time to time if you feel the need to
Food:
so as everyone knows everyone needs food in the RS community either ur F2P or or a members you need food, but the question is what do your flip? Do you flip the raw too? Well that's a pretty easy one ot answer as seeing swordfish, monkfish, and sharks tend to be the most popular among players so they tend to have really good margin. There could be more but those are usually the ones i tend to flip when i flip food.
Range:
So i don't have much to say bout range items but rune arrows and any kind of darts tend to be what does well, like i said i haven't mess around with this group of items much so play around with it alittle if you have something that can be add let me know 
Logs:
so with logs the ones i tend ot flip are the yew logs and ill flip magic logs here and there. Regular logs do ok here and there if u want to try them but there's not very many items put here besides those. Again if there are some logs you think i should try or there something i miss let me know
Ore:
Ok so here's one i've actually have messed around, there not really my favorite to flip so i don't usually flip them unless i have nothing else to flip. What tends to do pretty well is coal, adamantite, and runite ores. I recommend staying away from iron or as it tends to never really buy and sell that well but you can go for them if u want. There is also gold ore that are very good to flip, like i said i don't flip these too often so i don't know how well the prices are for these so if you decide to flip ores flip them at your own risk
misc.:
so here im kinda putting in things that are all around kind of weird flips, stuff that don't really fit into any real category and but there still relatively safe to flip but probably won't make u as much money as the other items i've noted above (cept zulrah scales) so the first thing i'm gonna name is zulrah scales. So zulrah scales is a weird one it usually has a consistant 2 gp margin but there in such a high demand and they have a huge buy limit that often times is worth to flip them at a 2gp margin making u upwards to 60-90k per flip depending on the margin. Another oddball one is supercompost, they have a small buy limit but usually has a very big margin. The final one im gonna say is Strength potions the reason i didn't really name other potions is cause stamina, prayer, and attack potion are very expensive so they're not good for small cash stacks of course if u have a big cash stack ur more then welcome to flip them. but strength potions are a very high demanding potion RS so there usually pretty good flips, atleast from what i've been told i personally haven't tried them but a lot of people usually recommend them and there fair cheap with a low buy limit so i figure i would add it to the misc. category due the fact i wasn't going to be naming other potions.
Well that's all i have for you guys, i hope that was very help for you and gave you a better understanding or gives you and idea of what to flip. Now these aren't all of the things u can flip at this amount of cash there are of course alot more u can flip if you choose but these are relatively safe flip, now i do use the term safe loosely as the u still have a chance to lose money off of these flips but the chances are very little and that's why i say there safe. If u have anything you want me to add or have any questions please to comment or message me privately. Good luck out there and happy flipping
P.S. can do a video if people need more of a visual tutorial 
i know how that can be im more a visual learning myself